Patent Publication Number: US-2017370456-A1

Title: Torque converter including front cover fluid flow baffles

Description:
The present disclosure relates generally to torque converters and more specifically to the fluid flow baffles in torque converters. 
     BACKGROUND 
     U.S. Pat. No. 8,327,636 discloses a torque converter including a front cover having blades for increasing a fluid flow toward or away from a clutch pack. U.S. Pat. No. 8,789,669 discloses torque converter drive plates that include at least one protrusion for disrupting a Coriolis Effect on fluid in the torque converter. 
     SUMMARY OF THE INVENTION 
     A torque converter is provided. The torque converter includes a front cover including a front radially extending section and a front axially extending section extending axially from an outer radial end of the front radially extending section. The torque converter also includes a plurality of baffle assemblies each including a base connected to the front radially extending section and a support connected to the base. Each of the baffle assemblies includes a first baffle and a second baffle extending radially inward from the respective support. 
     A method of forming a torque converter is also provided. The method includes providing a plurality of baffle assemblies each including a base, a support connected to the base and a first baffle and a second baffle extending from the support; and fixing the bases of the baffle assemblies to a radially extending section of the front cover such that the first and second baffle assemblies extend radially inward from the respective support. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described below by reference to the following drawings, in which: 
         FIG. 1  shows a cross-sectional side view of a torque converter including baffle assemblies according to an embodiment of the present invention; 
         FIG. 2  shows a stand-alone perspective view of one of the baffle assemblies; 
         FIG. 3  shows an enlarged cross-sectional side view of the front cover and one of the baffle assemblies; and 
         FIG. 4  shows a perspective view of the front cover including a plurality of baffle assemblies fixed thereto. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure provides front cover baffle assemblies to improve response time after coast engagement in a torque converter. The baffle assemblies are radially riveted to front cover and have a beneficial segmented geometry. The segmented baffle assemblies are designed to be nested and include segments bent from opposing sides to provide two baffles per baffle assemblies. 
       FIG. 1  shows a cross-sectional side view of a torque converter  10  in accordance with an embodiment of the present invention. Torque converter  10  is rotatable about a center axis  11  and includes a front cover  12  for connecting to a crankshaft of an internal combustion engine and a rear cover  14  forming a shell  16  of an impeller or pump  18 . The terms axially, radially and circumferentially as used herein are used with respect to center axis  11 . 
     Front cover  12  is substantially cup-shaped and includes a radially extending section  12   a  that intersects and extends radially away from center axis  11  and an annular axially extending section  12   b  that protrudes axially at an outer circumference of section  12   a . Section  12   b , near a rim thereof, is stepped radially inward to define a thinned section  12   c  having an outer circumferential surface  12   d . Rear cover  14  is similarly cup-shaped and includes a radially extending section  14   a  that forms impeller shell  16  and an annular axially extending section  14   b  that protrudes axially at an outer circumference of radially extending section  14   a . Near a rim  15  of section  14   b , section  14   b  is stepped radially outward to define a thinned section  14   c  having an inner circumferential surface  14   d . Covers  12 ,  14  are arranged with respect to each other such that sections  12   c ,  14   c  overlap each other, with section  12   c  being receiving inside of section  14   c  and outer circumferential surface  12   d  contacting inner circumferential surface  14   d . A weld  17  is provided at rim  15  and outer circumferential surface  12   d  of thinned section  12   c  to fix front cover  12  and rear cover  14  together. 
     Torque converter  10  also includes a turbine  20  configured to define a piston that is axially moveable toward and away from impeller  18  to engage and disengage an impeller clutch of impeller  18  so as to form a lockup clutch. Turbine  20  includes a turbine shell  22  and a core ring  24  supporting a plurality of turbine blades  26  therebetween. Turbine shell  22  includes a rounded blade supporting portion  28 , which is shaped as an annular bowl, for contacting engine side edges of turbine blades  26 . Radially outside of blade supporting portion  28 , an outer radial extension  30 , which forms the piston, radially protrudes outwardly from an outer circumference of blade supporting portion  28  to define an annular protrusion having a flat annular radially extending impeller facing surface  30   a  and having an outermost circumference that defines an outermost circumference of turbine  20 . Accordingly, the piston and turbine shell  22  are formed as a single piece. Radially inside of blade supporting portion  28 , turbine shell  22  includes an annular inner radial extension  31  that, at an inner radial end thereof, joins an axially extending inner circumferential section  33 , whose inner circumferential surface contacts an outer circumferential surface of a hub  35 . 
     Impeller  18  includes impeller blades  34 , which are each fixed at a transmission side thereof to impeller shell  16  and are each fixed to an impeller core ring  37  at an engine side thereof by tabs. Impeller shell  16 , at radially extending section  14   a  of rear cover  14 , includes a rounded blade supporting portion  32 , which is shaped as an annular bowl, for contacting transmission side edges of impeller blades  34 . Radially outside of blade supporting portion  32 , radially extending section  14   a  includes a radially extending wall  36 , which forms an impeller clutch, radially protrudes outwardly from an outer circumference of rounded blade supporting portion  32  to define an annular wall having a flat annular radially extending turbine facing surface  36   a . Accordingly, the impeller clutch and impeller shell  16  are formed as a single piece. Radially inside of blade supporting portion  32 , radially extending section  14   a  includes an annular inner radial extension  39  extending radially inward from blade supporting portion  32 . A radially inner end of extension  39  is connected to an impeller hub  41 . 
     A friction material  40  is bonded onto radially extending impeller facing surface  30   a  of outer radial extension  30  for engaging radially extending wall  36 . In other embodiments, instead of or in addition to being bonded to outer radial extension  30 , friction material  40  may be bonded to radially extending turbine facing surface  36   a  of radially extending wall  36 . Regardless of whether friction material  40  is bonded to outer radial extension  30  or radially extending wall  36 , friction material  40  is provided axially between surfaces  30   a ,  36   a.    
     Torque converter  10  also includes a stator  42  axially between turbine  20  and impeller  18  to redirect fluid flowing from the turbine blades  26  before the fluid reaches impeller  18  to increase the efficiency of torque converter  10 . Stator  42  includes a stator casting including a plurality of blades  46  and a stator body  48 . Stator  42  also includes a one-way clutch  50  held within stator body  48  by a centering plate  52 . An axial thrust washer  54 , which is axially between stator  42  and impeller  18 , is fixed to stator  42  at an outer circumference of centering plate  52 . 
     A damper assembly  62  is positioned between front cover  12  and turbine  20  and is configured for transferring torque from turbine  20  to a transmission input shaft. Damper assembly  62  includes two cover plates—a turbine side cover plate  64 , which is riveted to turbine  20 , and a front cover side cover plate  66 . Cover plates  64 ,  66  support a set of arc springs  68  axially therebetween. Damper assembly  62  also includes two drive flanges  70 ,  71  positioned axially between covers plate  64 ,  66 . Drive flange  70  includes an inner radial hub  72  configured for nonrotatably connecting to a transmission input shaft. Drive flanges  70 ,  71  both includes circumferentially extending slots for receiving springs  68 . Radially outside of springs  68 , cover plates  64 ,  66  are fixed together by a plurality of circumferentially spaced rivets  74 . 
     In accordance with an embodiment of the invention, torque converter  10  is provided with a plurality of circumferentially spaced baffle assemblies  76  connected to front cover  12 . Baffle assemblies  76  each includes a radially extending base  78  for contacting an inner radially extending surface  80  of radially extending section  12   a  of front cover  12 . Each baffle assembly  76  includes at least one arm  82  extending radially and axially from base  78  to a circumferentially and axially extending support  84 —circumferentially extending when viewed axially and axially extending when viewed circumferentially. The two opposing circumferential ends  84   a ,  84   b  ( FIG. 2 ) of support  84  are each provided with a respective baffle  86   a ,  86   b  extending radially inward from support  84 . Baffles  86   a ,  86   b  are radially aligned with damper assembly  62  and the overlapping sections  12   c ,  14   d  of covers  12 ,  14 , and are axially aligned with outer radial extension  30 . 
       FIG. 2  shows a stand-alone perspective view of one of baffle assemblies  76 . Base  78  is rectangular in shape and has a circumferential length greater than a radial length, such that a radially inner circumferentially extending edge  78   a  is longer than radially extending edges  78   b ,  78   c . Base  78  is provided with two holes  88  passing axially therethrough for receiving rivets  90  ( FIGS. 3, 4 ), with holes  88  extending from a first planar face  78   e  to a second planar face  78   f . Arms  82  are circumferentially spaced from each other by a radially extending slot  90 . Arms  82  each extend radially from a radially outer edge  78   d  of base  78  into a respective strengthening corrugation  92  for adding stiffness to each arm  82 . Radially outside of corrugation  92 , arms  82  each extend radially and axially at a curved segment  94  forming a radially outer end  82   a  of the respective arm  82 . Ends  82   a  merge with a first circumferentially extending edge  84   a  of support  84 . 
     Support  84  has a rectangular arc shaped—it has a rectangular shape when viewed radially and an arc shaped when viewed axially—and extends longitudinally in an arc-shaped path between two axially extending edges  84   b ,  84   c , which are shorter in length than circumferentially extending edges  84   a ,  84   d . Support  84  also includes an inner circumferential surface  84   e  and an outer circumferential surface  84   f , which are delimited by edges  84   a  to  84   d.    
     A first baffle  86   a  extends radially inward from axially extending edge  84   b  and a second baffle  86   b  extends radially inward from axially extending edge  84   cd . Baffles  86   a ,  86   b  are each rectangular in shape and each include a radially outer axially extending edge  96   a  that is coincident with the respective edge  84   b ,  84   c , a radially inner axially extending free edge  96   b  forming a radially innermost surface of the respective baffles  86   a ,  86   b  and two radially extending edges  96   c ,  96   d  extending radially from edge  96   a  to edge  96   b . Baffles  86   a ,  86   b  both also each includes an outer planar face  96   e  facing circumferentially away from baffle assembly  76  and an inner planar face  96   f  facing circumferentially toward baffle assembly  76 , with faces  96   e ,  96   f  being delimited by the respective edges  96   a  to  96   d . As shown, faces  96   e ,  96   f  are substantially wider than edges  96   a  to  96   d.    
       FIG. 3  shows an enlarged cross-sectional side view of the front cover  12  and one of the baffle assemblies  76 . Baffle assembly  76  is fixed to radially extending section  12   a  of front cover  12  by two rivets  90  passing through holes  88  ( FIG. 2 ) in base  78  and holes in radially extending section  12   a . Baffle assembly  76  is fixed in place such that a first planar face  78   e  of base  78  rests flush against inner radially extending surface  80  of radially extending section  12   a . Arms  82  protrude away from radially extending surface  80  at corrugations, then merge back toward front cover  12  at curved sections  94 . Curved sections  94  nest in an inner curved surface  100  of a bend  12   c  of front cover  12 , which joins radially extending section  12   a  and axially extending section  12   b . Outer circumferential surface  84   f  of support  84  rests flush against an inner circumferential surface  102  of axially extending section  12   b , with baffles  86   a ,  86   b  extending radially inward away from axially extending section  12   b.    
       FIG. 4  shows a perspective view of the front cover  12  including a plurality of baffle assemblies  76  fixed thereto by rivets  90 . In this embodiment, six circumferentially spaced baffle assemblies  76  are fixed to radially extending surface  80  of radially extending section  12   a  of front cover. Outer circumferential surfaces  84   f  of supports  84  contact inner circumferential surface  102  of axially extending section  12   b  of front cover and baffles  86   a ,  86   b  extending radially inward to impact fluid flow within torque converter  10 . 
     In the preceding specification, the invention has been described with reference to specific exemplary embodiments and examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense.