STATOR INCLUDING ONE-WAY CLUTCH HELD IN A STATOR BODY BY OUTER DIAMETER PORTIONS OF A COVER PLATE

A stator for a torque converter is provided. The stator includes a plurality of blades; a stator body supporting the blades and defining an annular recess formed therein; a one-way clutch in the annular recess; and a cover plate holding the one-way clutch in the annular recess. An outer diameter portion of the cover plate is received in a circumferentially extending groove of the stator body to axially fix the cover plate to the stator body.

The present disclosure relates generally to stators including one-way clutches and more specifically to torque converter stators.

BACKGROUND

Torque converter stators include cover plates holding a one-way clutch in a stator body.

SUMMARY

A stator is provided. The stator includes a plurality of blades; a stator body supporting the blades and defining an annular recess formed therein; a one-way clutch in the annular recess; and a cover plate holding the one-way clutch in the annular recess. An outer diameter portion of the cover plate is received in a circumferentially extending groove of the stator body to axially fix the cover plate to the stator body. The stator as recited in claim1wherein the circumferentially extending groove is within the annular recess and the stator body includes a rim portion radially overlapping the outer diameter portion of the cover plate.

In embodiments of the stator, the rim portion may include a radially extending surface defining a wall of the circumferentially extending groove and the radially extending surface of the rim portion may contact a radially extending surface of the outer diameter portion of the cover plate to axially fix the cover plate to the stator body. The rim portion may include a plurality of circumferentially spaced slots and a plurality of circumferentially spaced arc shaped rim segments. The stator body may circumferentially contact the cover plate to circumferentially fix the cover plate to the stator body. The cover plate may include a plurality of radially extending tabs and the stator body may circumferentially contact the radially extending tabs to circumferentially fix the cover plate to the stator body. The stator body may include a plurality of staked sections and each of the staked sections may contact a respective one of the radially extending tabs to circumferentially fix the cover plate to the stator body. The outer diameter portion of the cover plate may be formed by a plurality of radially extending tabs. Each of the radially extending tabs axially may contact a rim portion of the stator body to axially fix the cover plate to the stator body. The outer diameter portion of the cover plate may be formed by a plurality of circumferentially extending prongs. Each of the circumferentially extending prongs may include an outer radial protrusion axially contacting a rim portion of the stator body to axially fix the cover plate to the stator body.

A torque converter is provided including a turbine, an impeller and the stator axially between the turbine and the impeller.

A stator for a torque converter is also provided including a plurality of blades and a stator body supporting the blades. The stator body defines an annular recess formed therein. The stator also includes a one-way clutch within the annular recess, and a cover plate holding the one-way clutch within the annular recess. The cover plate includes radially extending tabs at an outer diameter thereof being received in a circumferentially extending groove of the stator body within the annular recess to axially fix the cover plate to the stator body. The stator body includes staked sections, and each of the radially extending tabs contacts a respective one of the staked sections to circumferentially fix the cover plate to the stator body.

The stator body may include a rim portion radially overlapping the radially extending tabs. The rim portion may include a plurality of circumferentially spaced arc shaped segments, and each of the radially extending tabs axially may contact a radially extending surface of a respective one of the circumferentially spaced arc shaped segments. The stator body may include a plurality of slots extending radially outward from the annular recess, and the slots may divide the rim portions into the plurality of circumferentially spaced arc shaped segments.

A method of forming a torque converter stator is also provided. The method includes providing a cover plate and a stator body including an annular recess; inserting a one-way clutch into the annular recess of the stator body; and axially fixing the cover plate to the stator body so the cover plate holds the one-way clutch in the stator body by inserting an outer diameter portion of the cover plate in a circumferentially extending groove of the stator body.

In some embodiments of the method, the outer diameter portion of the cover plate may be formed by a plurality of radially extending tabs. The circumferentially extending groove may formed by a plurality of circumferentially extending grooves and the stator body may include a plurality of slots extending radially outward from the annular recess. The inserting of the outer diameter portion of the cover plate in the circumferentially extending groove of the stator body may include pressing each of the tabs into a respective one of the slots, and rotating the cover plate to force each of the radially extending tabs into a respective one of the circumferentially extending grooves. The method may further include axially staking the stator body to circumferentially fix the cover plate to the stator body. The outer diameter portion of the cover plate may be formed by a plurality of circumferentially extending prongs and the circumferentially extending groove may be formed by a plurality of circumferentially extending grooves. The inserting of the outer diameter portion of the cover plate in the circumferentially extending groove of the stator body may include forcing the circumferentially extending prongs radially inward while pressing the cover plate into the annular recess.

DETAILED DESCRIPTION

FIG.1shows a cross-sectional side view of a torque converter10in accordance with an embodiment of the present disclosure. Torque converter10includes a front cover12for connecting to a crankshaft of an internal combustion engine and/or an output of an electric motor, and a rear cover14forming a shell16of an impeller or pump18. Torque converter10also includes a turbine20that is configured as a piston such that turbine20is axially moveable toward and away from impeller18to engage and disengage impeller18so as to form a lockup clutch. Turbine20includes a turbine shell22and an inner ring24supporting a plurality of turbine blades26therebetween. Turbine shell22includes a rounded blade supporting portion28for supporting of turbine blades26at a front cover side of the blades26. Radially outside of blade supporting portion28, turbine shell22includes an outer radial extension30radially protruding outwardly from an outer circumference of blade supporting portion28. Impeller shell16along with a core ring32, supports a plurality of impeller blades34.

A friction material36is bonded onto a surface of outer radial extension30for engaging impeller shell16. A damper assembly38is positioned between front cover12and turbine20and is configured for transferring torque from turbine20to a transmission input shaft via a hub40.

Outer radial extension30of turbine20engages impeller18via friction material36to transfer torque input into front cover20by the internal combustion engine crankshaft and/or the electric motor to the transmission input shaft. As turbine20is driven by impeller18, either through contact via friction material36and impeller shell16when the lockup clutch is locked or through fluid flow between blades26,34, turbine20transfers torque to damper assembly38, which in turn drives the transmission input shaft.

Torque converter10also includes a stator42axially between turbine20and impeller18to redirect fluid flowing from the turbine blades26before the fluid reaches impeller18to increase the efficiency of torque converter10as turbine20, impeller18and stator42rotate about a center axis CA of torque converter10. Unless otherwise specification, the terms radial, axial and circumferential and derivatives thereof are used herein reference to center axis CA. Stator42includes a stator casting44including a plurality of stator blades46and a stator body48. Stator42also includes a one-way clutch50held within stator body48by a cover plate52. A portion of an outer diameter of cover plate52is held in at least one circumferentially extending groove54formed in stator body48. One-way clutch50includes an inner race56, an outer race58and rollers60and springs62(FIG.4b) radially between inner race56and outer race58.

Stator casting44is rotationally fixed to outer race58, and depending on the operating conditions of torque converter10, inner race56and outer race58are rotationally fixed to each other or rotatable relative to each other. When impeller18rotates faster than turbine20and stator42is stationary, springs62circumferentially offset from rollers60press rollers60into wedged surfaces to rotationally fix inner and outer races56,58together, preventing rotation of stator casting44and causing stator42to redirects the fluid flowing from turbine20to impeller18. When impeller18and turbine20are rotating at substantially the same speed, inner race56and outer race58are rotatable relative to each other, and stator42rotates in same direction as impeller18and does not redirect the fluid flowing from turbine20to impeller18.

FIG.2shows an enlarged cross-sectional side view of stator42that is circumferentially offset from the view of stator42shown in torque converter10inFIG.1. Stator42includes blades46for redirecting the torque converter fluid extending radially outward from an outer circumferential surface64of stator body48. Stator body48includes, on axially opposite sides of stator body48, a first axially facing side48aand a second axially facing side48b.First axially facing side48aincludes a radially extending surface68extending axially inward from outer circumferential surface64of stator body48. Stator body48defines an annular recess66formed in first axially facing side48aextending axially away from radially extending surface68. Annular recess66receives one-way clutch50. Annular recess66is defined by two step portions—a radially inner step portion70receiving inner race56and a radially outer step portion72receiving rollers60and outer race58. Radially inner step portion70includes a radially extending surface70aextending radially outward from an innermost circumferential surface74of stator casting44and an axially extending circumferential surface70bextending from a radially outer edge of radially extending surface70a.Radially outer step portion72includes a radially extending surface72aextending radially outward from axially extending circumferential surface70bof step portion70and an axially extending circumferential surface72bextending from a radially outer edge of radially extending surface72atoward first axially facing side48a.

Stator casting44also includes circumferentially extending grooves54within annular recess66. Circumferentially extending grooves54are each positioned axially between second step portion72and radially extending surface68. Circumferentially extending grooves54are defined on a first axial side by radially outer step portion72and a second axial side by a rim portion76. More specifically, rim portion76, which is defined by on the first axial side48aby surface68, includes a radially extending surface76adefining a first radially extending wall of groove54, and radially outer step portion72includes a radially extending surface72c,which extends radially from axially extending surface72b,defining a second radially extending wall of groove54. An axially extending surface54aextends axially from surface72cto surface76a,to define an axially extending outer circumferential wall of groove54.

As shown clearly inFIG.3, which illustrates an exploded view of stator42, an outer diameter portion of cover plate52is configured for being received in circumferentially extending grooves54to axially fix cover plate52to stator body48. More specifically, cover plate52includes an outer diameter portion in the form of a plurality of circumferentially spaced tabs78at the outer diameter thereof that define outermost circumferential surfaces80aof cover plate52. The outer circumference of cover plate52, in addition to outermost circumferential surfaces78a,further includes radially innermost surfaces80bthat are directly circumferentially adjacent to surfaces80a,and radially intermediate surfaces80cthat are radially closer to center axis CA than surfaces80abut radially further from center axis CA than surfaces80b.Tabs78also include a first radially extending surface80don a first circumferential side of the tab78extending radially outward from the respective surface80bto surface80aand a second radially extending surface80eon a second circumferential side of the tab78extending radially outward from the respective surface80bto surface80a.

In the example shown inFIG.3, tabs78are bounded by surfaces80bon both circumferential sides thereof and surfaces80care bounded by surfaces80bon both circumferential sides thereof, such that each surface80bis directly circumferentially between one surface80aand one surface80c.The radial inward offset of surfaces80bwith respect to the directly adjacent surfaces80a,80cdefines a plurality notches82in the outer circumference of cover plate52. Each of notches82is directly circumferentially adjacent to one of tabs78such that tabs78are each directly circumferentially adjacent to two notches82.FIG.3further shows inner race56and outer race58removed from annular recess66in stator body48and allows viewing circumferentially extending grooves54. Inner race56includes an inner splined surface56afor connecting to a stator shaft and outer race58includes an outer splined surface58afor connecting to axially extending surface72bof radially outer step portion72. Circumferentially extending grooves54extend circumferentially with respect to center axis CA and as noted above are defined by surfaces54a,72c,76a.

FIG.4ashows a standalone perspective view of stator casting44allowing a clear view of annular recess66and circumferentially extending grooves54andFIG.4bshows a view of stator42with cover plate52omitted. In order for cover plate52to be installed in circumferentially extending grooves54, rim portion76is provided with a plurality of circumferentially spaced slots84—one slot84for each tab78—that allow tabs78of cover plate52to axially pass through as cover plate52is pressed axially into annular recess66. Slots84extends radially outward from axially extending surface72bof radially outer step portion72past axially extending surface54aof grooves54to divide rim portion76into a plurality of circumferentially spaced arc shaped segments76b.Each arc shaped segment76bincludes a staked section86that is formed in rim portion76after cover plate52is inserted into annular recess66. Staked sections86each circumferentially abut one of tabs78and are received in one of notches82to lock cover plate52circumferentially into place in circumferentially extending grooves54. Staked sections86each include an indentation86aformed axially into radially extending surface68on first axially facing side48aof stator body48and a protrusion86bextending axially from radially extending surface76aof rim portion76into the respective circumferentially extending groove54. Stator body48circumferentially contacts cover plate52to circumferentially fix cover plate52to stator body48. More specifically, circumferential edge86cof each protrusion86bcontacts a respective radially extending surface80dor80eof one of tabs78to prevent circumferential movement of cover plate52within circumferentially extending grooves54.

FIG.5shows an enlarged view of a portion of stator body48shown inFIG.4illustrating the details of one of slots84and one of stacked sections86. Slot84includes an axially extending surface84aextending from radially extending surface68and a radially extending surface84bextending radially inward from surface84ato axially extending surface72b.Slot84has an axial depth that is greater than an axial depth of circumferentially extending groove54such that surface84bis recessed in the axial direction from surface72cof groove54. Slot84also has radial depth that is greater than a radial depth of circumferentially extending groove54such that surface84ais recessed in the axial direction from surface54aof groove54. This radial depth reduces stiffness with respect to surface72bof stator body48comprising against splines58aof outer race58and therefore reduces the stress state in stator casting44.

FIG.6shows a cross-sectional view of a portion of stator42illustrating one of tabs78being received in circumferentially extending groove54. Rim portion76radially overlaps the outer diameter portion, i.e., tabs78, of cover plate52. A first radially extending axial facing surface78aof tab78contacts radially extending surface76aof rim portion76and a second radially extending axial facing surface78bof tab78, which is axially opposite of surface78a,is axially spaced from radially extending surface72cby a distance X1such that tabs78each have an axial thickness X2that is less than an axial depth X3of circumferentially extending groove54between surfaces76a,72c.Outermost circumferential surfaces80aof cover plate52, defined by tabs78, are radially spaced from axially extending surface54a,by a distance X4, which is for example 2 mm or greater. Rim portion76has an axial thickness X5, which is for example 2 mm or greater. A radially extending axial facing surface52aof cover plate52, which is on the same side of cover plate52as surfaces78bof tab78, axially contacts outer race58.

FIGS.7to11illustrates a method of constructing stator42by installing cover plate52into annular recess66and fixing tabs78of cover plate52in circumferentially extending grooves54. It is noted that one-way clutch50is omitted fromFIGS.7to11, but one-way clutch50is installed inside of annular recess66before cover plate52is inserted into annular recess66. After one-way clutch50is installed inside of annular recess66, as shown inFIG.7, tabs78are each axially aligned with one of slots84, and cover plate52is pressed into annular recess66such that each of tabs78enters the respective one of slots84such that axially facing surface78aof each of tabs78is in the recess66further from surface68than radially extending surface76aof rim portion76is from surface76.

After tabs78are inserted into grooves54, as shown inFIG.8, cover plate52is rotated in a rotational direction D1a desired angular degree such that each of tabs78is movable circumferentially away from the respective slot84and into axial alignment with and a respective one of arc shaped segments76bof rim portion76and surface78aof each tab78is directly axially facing the respective surface76a.Circumferential stops may be provided in each circumferentially extending groove54for each of tabs78to contact the respective tab78and indicate when the tabs78are in the correct angular orientation. Circumferential stops may be angularly positioned every n/360 degrees, where n is the number of tabs78. For example, in the example shown inFIGS.7to11, with four tabs78, circumferential stops may be positioned every ninety degrees in circumferentially extending grooves54(i.e., 4/360=90).FIG.9illustrates one of tabs78axially aligned with and the respective one of arc shaped segments76b.

As illustrated inFIGS.10and11, after tabs78are rotated the desired angular degree, rim portion76of stator body48is staked with a staking tool to form a plurality of staked section86. More specifically, in the example inFIGS.10and11, each of arc shaped segments76bof rim portion76is staked to form a staked section86therein. In other words, each staked section86is circumferentially between two of the slots84. At least one of the staked sections86(two in the example shown inFIG.10) prevents rotation in direction D1and at least one of the staked sections86(two in the example shown inFIG.10) prevents rotation in direction D2, which is opposite of direction D1. More specifically, two of staked sections86contact the first radially extending surface80don the first circumferential side of the respective tab78and two of staked sections86contact the second radially extending surface80eon the first circumferential side of the respective tab78. The staked sections86that contact surfaces80dthus prevent rotation in direction D2and the staked sections86that contact surfaces80ethus prevent rotation in direction D1.

FIGS.12to15illustrate a further example of a cover plate152for fixing in an annular recess166of a stator body148. Unless specified below and illustrated inFIGS.12,13and15, stator body148is configured in the same manner as stator body48and annular recess166is configured in the same manner as annular recess66.FIG.12shows a plan view of cover plate152in stator body148, andFIG.13shows a view of an enlarged portion ofFIG.12.FIG.14shows a standalone perspective view of cover plate152. As shown inFIGS.12and13, cover plate152is axially fixed in place by an outer diameter portion of cover plate152in the form of circumferentially extending prongs156at the outer diameter of cover plate152. Stator body148circumferentially contacts cover plate152to circumferentially fix cover plate152to stator body148. More specifically, tabs178fix cover plate152rotationally in place in stator body148by engaging with slots184formed in stator body148. Tabs178each include two opposite radially extending surfaces178a,178bthat contact radially extending surfaces184a,184bof the respective slot184to fix cover plate152radially in place in annular recess166of stator body148. Stator body148is provided with circumferentially extending grooves154each configured for receiving a respective one of prongs156. Stator body148includes a rim portion176formed by a plurality of circumferentially spaced arc shaped segments176band each of grooves154is formed in part by one of segments176b.

As shown inFIGS.12to14, an inner circumferential surface of each of prongs156is formed by a circumferentially extending slot190formed in cover plate152and each prong156is provided with a protrusion156aon the outer circumferential surface thereof. Each of protrusions156aprotrudes radially further than a remainder of the outer circumferential surface156bof prong156. Each protrusion156ais received in circumferentially extending groove154to hold cover plate152axially in place with respect to stator body148by contacting the respective segment176bin the respective groove154.

As illustrated inFIG.15, which shows a cross-sectional view of cover plate152and stator body148along A-A inFIG.12, a radially extending surface176aof rim portion176contacts protrusion156aat an axially facing radially extending surface156cof prong156to fix cover plate152axially in place in annular recess166of stator body148.

After one-way clutch50(FIG.1) is installed inside of annular recess166, tabs178are each axially aligned with one of slots184, and cover plate152is pressed into annular recess166such that each of tabs178enters the respective one of slots184and protrusions156aof prongs are inserted into the corresponding groove154. Prongs156are pressing radially inward to move prongs156axially past rim portion176. More specifically, prongs156are pressed radially inward such that an outermost circumferential surface156dof each prong156(i.e., the outer circumferential surface of each protrusion156a) is radially inward from an inner circumferential surface176cof the respective rim portion176. A chamfer surface156eof each prong156may contact a chamfer surface176dof the respective rim portion176to force prongs156radially inward.

In the preceding specification, the present disclosure 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 present disclosure 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.

LIST OF REFERENCE NUMERALS

10torque converter12front cover13rear cover16impeller shell18impeller20turbine22turbine shell24turbine inner ring26turbine blades28rounded blade supporting portion of turbine shell30outer radial extension of turbine shell32impeller core ring34impeller blades36friction material38damper assembly40damper hub42stator44stator casting46stator blades48stator body48afirst axially facing side48bsecond axially facing side50one-way clutch52cover plates52aradially extending axial facing surface54annular groove54aaxially extending surface defining annular groove56inner race58outer race60rollers62springs64stator body outer circumferential surface66stator body annular recess68radially extending surface on first axially facing side of stator body70radially inner step portion in stator body annular recess70aradially extending surface of radially inner step portion70baxially extending surface of radially inner step portion72radially outer step portion in stator body annular recess72afirst radially extending surface of radially outer step portion72baxially extending surface of radially outer step portion72csecond radially extending surface of radially outer step portion74innermost circumferential surface of stator casting76rim portion of stator body76aradially extending surface of rim portion76bcircumferentially spaced arc shaped segments of rim portion78circumferentially spaced outer diameter tabs of cover plate78afirst radially extending axial facing surface of tabs78bsecond radially extending axial facing surface of tabs80aoutermost circumferential surfaces of cover plate80bradially inner outer circumferential surfaces of cover plate80cradially intermediate outer circumferential surfaces of cover plate80dradially extending surfaces of the outer circumference of cover plate82outer circumference notches in cover plate84circumferentially spaced slots86staked section of rim portion86aindentation of staked section86bprotrusion of staked section86ccircumferential edge of protrusion148stator body152cover plate154circumferentially extending grooves156circumferentially extending prongs156aouter circumferential surface radial protrusion of prongs156bouter circumferential surface of prongs156caxially facing radially extending surface of prong156doutermost circumferential surface of prong156echamfer surface of prongs166annular recess176rim portion of stator body176aradially extending surface of rim portion176bcircumferentially spaced arc shaped segments of rim portion176cinner circumferential surface of rim portion176dchamfer surface of rim portion178tabs178afirst radially extending axial facing surface of tabs178bsecond radially extending axial facing surface of tabs184slots184afirst radially extending surfaces of slots184bsecond radially extending surfaces of slots190circumferentially extending slot in cover plate