Stator assembly of hydrokinetic torque converter with press crimped retainer plates and method for making the same

A stator assembly of a hydrokinetic torque converter includes a stator rotatable about an axis and having a hub bore coaxial to the axis, the stator having a crimped portion, a one-way clutch mounted to the stator in the hub bore coaxially to the axis, and a retainer plate fixedly secured to the stator in hub bore by the crimped portion. A method for making a stator assembly of a hydrokinetic torque converter involves providing a stator having an axis and a hub bore that is coaxial with the axis, the hub bore containing a one-way clutch and an annular retainer plate, and crimping a portion of the stator to fixedly secure the one-way clutch and the annular retainer plate in the hub bore.

BACKGROUND

This invention generally relates to hydrokinetic torque converters, including the arrangement of a stator and a one-way clutch in a hydrokinetic torque converter.

Typically, a hydrokinetic torque converter includes a drive pump (or impeller), a driven turbine, a stator (or reactor) fixed to a case of the torque converter, and a one-way clutch for restricting a rotational direction of the stator to one direction. The turbine is integral or operatively connected with a hub linked in rotation to a driven shaft, which is itself linked to an input shaft of a transmission of a vehicle. The turbine works together with the impeller, which is linked in rotation to a casing that is linked in rotation to a driving shaft driven by an internal combustion engine. The stator is interposed axially between the turbine and the impeller, and is mounted so as to rotate on the driven shaft with the interposition of the one-way clutch.

While hydrokinetic torque converters, including but not limited to that discussed above, have proven to be acceptable for vehicular driveline applications and conditions, improvements that may enhance their performance and cost are possible.

BRIEF SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a stator assembly for a hydrokinetic torque converter, the stator assembly including a stator rotatable about an axis and providing an annular hub bore coaxial to the axis, a one-way clutch mounted to the stator in the hub bore coaxially to the axis, and a retainer plate. The stator is crimped to fixedly secure the retainer plate and retain the one-way clutch in the hub bore.

According to a second aspect of the present invention, there is provided a method for making a stator assembly of a hydrokinetic torque converter. A stator is provided having an axis and a hub bore that is coaxial with the axis, the hub bore containing a one-way clutch and an annular retainer plate. A portion of the stator is crimped to fixedly secure the one-way clutch and the annular retainer plate in the hub bore.

The method involve the steps of providing a stator having an axis and an annular hub bore coaxial to the axis, mounting a one-way clutch in the hub bore of the stator, providing an annular retainer plate, inserting the annular retainer plate into the hub bore of the stator so that the one-way clutch is positioned in the hub bore between the stator and the retainer plate, and subsequently deforming the stator radially inwardly toward the retainer plate and thereby fixedly securing the annular retainer plate to the stator by a crimping operation so as to sandwich the one-way clutch between the stator and the annular retainer plate.

Other aspects of the invention, including apparatus, devices, systems, converters, processes, and the like which constitute part of the invention, will become more apparent upon reading the following detailed description of the exemplary embodiments.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT(S) AND EMBODIED METHOD(S) OF THE INVENTION

Reference will now be made in detail to exemplary embodiments and methods of the invention as illustrated in the accompanying drawings, in which like reference characters designate like or corresponding parts throughout the drawings. It should be noted, however, that the invention in its broader aspects is not limited to the specific details, representative devices and methods, and illustrative examples shown and described in connection with the exemplary embodiments and methods.

This description of exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description, relative terms such as “horizontal,” “vertical,” “up,” “down,” “upper”, “lower”, “right”, “left”, “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship. Additionally, the word “a” and “an” as used in the claims means “at least one” and the word “two” as used in the claims means “at least two”.

A stator assembly suitable for use in a hydrokinetic torque converter is generally represented in the accompanying drawings by reference numeral10, as best shown inFIG. 2. The stator assembly10is typically mounted between an impeller (not shown) and a turbine (not shown) of the torque converter.

The stator assembly10is rotatable about an axis X and comprises a stator (or reactor)12, a one-way (or overrunning) clutch14disposed between the stator12and a stator shaft (not shown), a turbine (or first) thrust bearing16amounted between the stator12and a turbine (not shown) and provided at a radially inner portion of the turbine, and a pump (or second) thrust bearing16bmounted between the stator12and an impeller (or pump) (not shown) and provided at a radially inner portion of the impeller. The one-way clutch14permits rotation of the stator12in one direction only. The turbine thrust bearing16aand the pump thrust bearing16bare provided to allow the relative rotation of the stator12with respect to the turbine and to the impeller. The turbine thrust bearing16aand the pump thrust bearing16bmay be of any appropriate design, such as a needle bearing.

The stator12is in the form of a cylindrical ring so as to define a stator hub18coaxial to the axis X, and a plurality of vanes20extending radially outwardly from the stator hub18, which is located radially inward and central to the vanes20. The first thrust bearing16ais mounted operatively between the stator hub18and the turbine, while the second thrust bearing16bis mounted operatively between the stator hub18and the impeller. As best shown inFIGS. 1 and 3, the first thrust bearing16aand the second thrust bearings16bare mounted on axially opposite sides of the stator hub18.

As best shown inFIG. 4, the stator hub18includes an annular base wall30coaxial to the axis X, and a transverse wall32extending radially inwardly from the base wall30so as to define an axial annular hub bore34coaxial to the axis X. The axial annular hub bore34within the stator hub18is delimited by a cylindrical inner peripheral surface31of the base wall30and an annular inner transverse surface33iof the transverse wall32. The cylindrical inner peripheral surface31of the base wall30extends substantially coaxially to the axis X, while both the inner transverse surface33iand an annular outer transverse surface33oof the transverse wall32extend substantially perpendicular to the axis X.

The base wall30of the stator hub18has a main portion30m, a first axially distal end portion30a, and a second axial distal end portion30b. The first and second axially distal end portions30a,30bare defined at axially opposite distal ends of the stator hub18. The transverse wall32is disposed adjacent to but spaced from the second axially distal end portion30bof the base wall30. The transverse wall32is closer to the second axially distal end portion30bthan to the first axially distal end portion30aof the base wall30. Alternatively, the transverse wall32may be disposed closer to the first axially distal end portion30aof the base wall30, or half-way between the first and second distal end portions30a,30b. The transverse wall32includes one or more support tabs38extending radially inwardly from the transverse wall32.

The main portion30mof the base wall30of the stator hub18includes a substantially cylindrical main inner surface36mcoaxial with the axis X. The first axially distal end portion30aof the base wall30of the stator hub18includes a substantially annular, for example substantially cylindrical, end inner surface36scoaxial with the axis X. The main inner surface36mand the end inner surface36sare joined by an annular contact surface36cextending between the inner support surface36sand the main inner surface36m. The annular contact surface36cis oriented substantially orthogonally relative to the axis X. The main inner surface36m, the end inner surface36sand the contact surface36ccollectively define the inner peripheral surface31of the hub bore34.

The hub bore34within the stator hub18can be viewed as being divided into a cylindrical bearing central bore portion35adelimited by the main inner surface36mof the base wall30and the inner transverse surface33iof the transverse wall32, and a substantially annular end bore portion35barranged at the first axially distal end portion30aof the base wall30and delimited by the inner support surface36sand the annular contact surface36c. A diameter of the cylindrical main inner surface36mof the central bore portion35ais less than a diameter of the annular inner support surface36sof the end bore portion35bof the first axially distal end portion30bof the base wall30of the stator hub18. The central bore portion35aand the end bore portion35bare adjacent to one another to collectively form the hub bore34.

The one-way clutch14is disposed substantially in the cylindrical bearing central bore portion35a(FIG. 4) of the hub bore34of the stator hub18coaxially to the axis X. The one-way clutch14, as best shown inFIGS. 1 and 4, includes an outer ring24non-rotationally secured (e.g., fixed) to the stator hub18coaxially to the axis X, an inner ring26coaxial to the axis X, and a plurality of sprags or cylindrical rollers28circumferentially disposed in an annular space defined between the outer ring24and the inner ring26. An inner peripheral surface of the inner ring26has splines27for rotatably coupling to an outer periphery of a stator shaft. The outer ring24is mounted within the hub bore34coaxially to the axis X so as to non-rotatably engage the main inner surface36mof the bearing bore portion35aof the base wall30. The outer ring24can be toothed externally and force-fit into the main inner surface36mof the bearing bore portion35aso as to non-rotatably secure the outer ring24of the one-way clutch14to the stator hub18of the stator12. The outer ring24abuts against the inner transverse surface33iof the transverse wall32to axially position the outer ring24in the axial cylindrical bearing bore portion of the stator hub18.

The stator assembly10includes a substantially annular retainer plate40mounted to the stator hub18adjacent to the first axially distal end portion30aof the base wall30of the stator hub18. The retainer plate40is provided to retain the one-way clutch14in the cylindrical hub bore34of the stator hub18and to prevent axial movement of the components of the one-way clutch14in the direction of the axis X relative to the stator hub18. As best shown inFIGS. 1-3, the retainer plate40includes a substantially annular, planar retainer ring42and one or more retainer tabs44extending radially inwardly from the plate ring42. An outer diameter of the retainer plate40is larger than the diameter of the cylindrical main inner surface36mof the bearing bore portion35a, but approximately equal to or slightly smaller than the diameter of the annular inner support surface36sof the end bore portion35b.

The stator retainer plate40has an axially inner end face engaging both the outer ring24and the inner ring26of the one-way clutch14so as to retain the sprags or cylindrical rollers28between the transverse wall32and the retainer plate40within the cylindrical bearing bore34of the stator hub18. An axially outer end face of the stator retainer plate40engages the first thrust bearing16a. The retainer plate40is secured at the first axially distal end portion30aof the base wall30of the stator hub18by a press-crimping action in such a manner as to fixedly (i.e., non-movably) attach the retainer plate40to the stator12. As best shown inFIG. 3, a crimped portion of the distal end portion38ais represented by reference numeral56a. Moreover, the retainer plate40is mounted to the first axially distal end portion30aof the base wall30of the stator hub18so as to be disposed within the end bore portion35bof the stator hub18delimited by the inner support surface36sand the annular contact surface36c, but outside the central bearing bore portion35a.

As best illustrated inFIG. 4, the second axially distal end portion30bof the base wall30of the stator hub18includes a substantially annular inner support surface37scoaxial with the cylindrical peripheral surface31of the base wall30. In the exemplary embodiment of the present invention, the annular outer transverse surface33oof the transverse wall32is oriented substantially orthogonally relative to the axis X.

Each of the first and second thrust bearings16aand16bincludes a pair of bearing races, specifically an outer (or first) bearing race45and an inner (or second) bearing race46. A plurality of rollers48are rotatably positioned between the outer and inner bearing races45,46. The first and second thrust bearings16aand16bare mounted to bearing rings50aand50b, respectively, and are non-movably secured (i.e., fixed) to the stator hub18. The first thrust bearing16aand first bearing ring50amay be substantially structurally and geometrically identical to the second thrust bearing16band the second bearing ring50b, as shown. Alternatively, the first and second thrust bearings16a,16band the bearing ring50a,50bthereof may be structurally and/or geometrically different from one another.

The first thrust bearing16ais mounted to the first axially distal end portion30aof the base wall30of the stator hub18. Specifically, the first thrust bearing16ais mounted to the retainer plate40disposed at the first axially distal end portion30aof the base wall30of the stator hub18that faces the turbine. As best shown inFIG. 3, an outer diameter of the bearing ring50ais larger than a diameter of the bearing bore portion35aof the hub bore34, but slightly smaller than the diameter of the end bore portion35bof the hub bore34, i.e., the diameter of the annular inner support surface36sof the first axially distal end portion30a. The bearing ring50ais mounted to the first axially distal end portion30aof the base wall30of the stator hub18so as to be disposed within the end bore portion35bof the hub bore34delimited by the inner support surface36sand the annular contact surface36c, but outside the central bearing bore portion35aof the hub bore34. In the assembled condition of the stator assembly10, the retainer plate40is disposed between the one-way clutch14and the bearing ring50a. The crimped portion56aretains the bearing ring50ain place.

The bearing ring50bof the second thrust bearing16bis mounted to the second axially distal end portion30bof the base wall30so as to axially engage the outer transverse surface33o(FIG. 4) of the transverse wall32, and radially engage a bearing support surface38bof the support tabs38of the transverse wall32. Thus, the stator hub18of the stator12defines a thrust bearing-receiving recessed section35cdelimited by the inner support surface37s, the outer transverse surface33oof the transverse wall32, and the bearing support surface38bfor receiving the second thrust bearing16b. The second axially distal end portion30bof the base wall30of the stator hub18is deformed radially inwardly toward the bearing ring50bthereby securing the bearing ring50bof the second thrust bearing16bto the stator12. A press-crimping operation may be used to deform the second axially distal end portion30b. The deformed, crimped portion is represented inFIG. 3by reference numeral56b. As a result, the inner support surface37sof the second axially distal end portion30bof the base wall30of the stator hub18fixedly (i.e., non-movably) engages a cylindrical outer peripheral surface of the bearing ring50bof the second thrust bearing16b.

As best illustrated inFIG. 2, the bearing ring50aof the first thrust bearing16aincludes one or more indentations (or grooves)52formed at a peripheral edge of the bearing ring50a, while the retainer plate40includes one or more indentations (or grooves)43formed at a peripheral edge of the planar retainer ring42of the retainer plate40. The number and circumferential positions of the indentations43of the retainer plate40are the same as the indentations52of the bearing ring50a. As illustrated, the retainer plate40and the bearing ring50aeach include six (6) indentations43and52. The indentations43of the retainer plate4and the indentations52of the bearing ring50aare substantially geometrically identical in the direction perpendicular to the axis X.

The first axially distal end portion30aof the base wall30of the stator hub18includes one or more protrusions54extending radially inwardly and complementary to the indentations43of the retainer plate40and the indentations52of the bearing ring50a. In the illustrated embodiment, the number of the protrusions54of the stator hub18equals to the number of the indentations43and52of the retainer plate40and the bearing ring50a. According to the exemplary embodiment of the present invention, the stator hub18includes six (6) protrusions54.

The indentations43and52of the retainer plate40and the bearing ring50a, respectively, and the protrusions54of the stator hub18define an anti-rotation mechanism that prevents the rotation of the retainer plate40and the bearing ring50arelative to the stator hub18. The anti-rotation mechanism may undertake alternative forms. For example, the protrusion or protrusions may be provided on the retainer plate40and the bearing ring50, while the indentation or indentations may be provided in the first axially distal end portion30aof the base wall30of the stator hub18, wherein the indentation(s) and protrusion(s) are complementary to one another.

Described below is an exemplary method whereby the stator assembly10of a hydrokinetic torque converter according to the exemplary embodiment of the present invention is assembled. It should be understood that alternative methods may be practiced within the scope of the invention.

According to an embodied method, the stator12is machined to form a single-piece part defining the hub bore34and having an axis X. The one-way clutch14is mounted to the stator12in the bearing bore portion35aof the hub bore34. The one-way clutch14may be mounted as follows. The outer ring24of the one-way clutch14is axially inserted into the bearing bore portion35auntil the outer ring24axially engages the inner transverse surface33iof the transverse wall32. A press fitting operation may be used to insert the outer ring24into the cylindrical main inner surface36mof the base wall30so as to non-rotatably secure the outer ring24of the one-way clutch14to the stator hub18of the stator12. The inner ring26of the one-way clutch14is axially inserted into the stator hub18until the inner ring26axially engages a clutch support surface38bof the support tabs38of the transverse wall32. The sprags or cylindrical rollers28are circumferentially placed in the annular space defined between the outer ring24and the inner ring26. The elements24,26, and28may be inserted into the hub bore34in any order or simultaneously.

The annular retainer plate40, which may be made by metal stamping, is mounted to the stator hub18of the stator12by inserting the annular retainer plate40into the end bore portion35bof the stator hub18until the annular retainer plate40axially engages at least one of the outer ring24of the one-way clutch14, the inner ring26of the one-way clutch14, and/or the contact surface36cof the first axially distal end portion30aof the base wall30of the stator hub18. The annular retainer plate40is thereby disposed within the end bore portion35b, but outside the bearing bore portion35a, while the one-way clutch14is positioned within the hub bore34between the transverse wall32of the stator hub18and the annular retainer plate40. While or immediately after the retainer plate40is inserted into the end bore portion35bin the stator hub18, the retainer plate40is oriented so that the indentations43in the retainer plate40engage the protrusions54on the first axially distal end portion30aof the base wall30of the stator hub18.

The first thrust bearing16ais mounted to the stator hub18of the stator12by inserting the bearing ring50ainto the end bore portion35bof the stator hub18until the bearing ring50aaxially engages the annular retainer plate40. The bearing ring50ais also disposed within the end bore portion35bof the hub bore34, but outside the bearing bore portion35a. While or immediately after the bearing ring50ais inserted into the end bore portion35bin the stator hub18, the bearing ring50ais oriented so that the indentations52in the bearing ring50aengage the protrusions54on the first axially distal end portion30aof the base wall30of the stator hub18.

The second thrust bearing16bis mounted to the stator hub18of the stator12by inserting the bearing ring50bthereof into the thrust bearing receiving recessed section35cin the stator hub18until the bearing ring50baxially engages the traverse wall32of the stator hub18.

Next, the first axially distal end portion30aof the base wall30of the stator hub18is deformed radially inwardly toward the retainer plate40and the bearing ring50aby a crimping operation to form the crimped portion56a. The retainer plate40and the bearing ring50aare thereby non-rotatably and axially non-movable secured to the stator12, with the one-way clutch14sandwiched between the transverse wall32of the stator12and the annular retainer plate40. The press-crimping operation may be performed simultaneously using a circular crimping press60(shown inFIG. 5). The crimping press60includes a lower circular crimping tool62and an upper circular crimping tool64with the crimping tools62and64movable relative to each other. During the crimping operation, first, the stator12, with the one-way clutch14, the retainer plate40, and the first and second thrust bearings16aand16bmounted thereon, is placed and centered on the lower crimping tool62. The stator12is disposed on the lower crimping tool62coaxially therewith. Then, the crimping press60is activated and the upper crimping tool64moves toward the lower crimping tool62and the stator12. In other words, the upper crimping tool64moves axially toward the stator12in the direction substantially parallel to the axis X. Upon engagement with the stator12, the upper crimping tool64contacts an outer peripheral surface or sections of the first axially distal end portion30aof the base wall30of the stator hub18as illustrated inFIG. 6. By further moving the upper crimping tool64axially inwardly relative to the stator12, the crimping force Fc is applied by the upper crimping tool64to the first axially distal end portion30aof the base wall30of the stator hub18, as shown inFIG. 6. As a result, the annular end inner surface36sof the first axially distal end portion30aof the base wall30of the stator hub18is deformed radially inwardly toward the retainer plate40and the bearing ring50aso as to fixedly (i.e., non-movably) engage a cylindrical outer peripheral surface of the retainer plate40and a cylindrical outer peripheral surface of the bearing ring50aof the first thrust bearing16a.

Similarly, as the crimping force Fc is applied to the first axially distal end portion30aof the base wall30of the stator hub18by pressing the upper crimping tool64against the stator12, the second axially distal end portion30bof the base wall30of the stator hub18, an outer peripheral surface of which is in contact with the lower crimping tool62, is also deformed radially inwardly toward the bearing ring50bthereby non-rotatably and axially non-movable securing (i.e., fixing) the bearing ring50bof the second thrust bearing16bto the stator12by a press-crimping action to form crimped portion56b. As a result, the inner support surface37sof the second axially distal end portion30bof the base wall30of the stator hub18fixedly (i.e., non-movably) engages a cylindrical outer peripheral surface of the bearing ring50bof the second thrust bearing16b.

The foregoing description of the exemplary embodiment(s) of the present invention has been presented for the purpose of illustration in accordance with the provisions of the Patent Statutes. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. The embodiments disclosed hereinabove were chosen in order to best illustrate the principles of the present invention and its practical application to thereby enable those of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as suited to the particular use contemplated, as long as the principles described herein are followed. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains. Thus, changes can be made in the above-described invention without departing from the intent and scope thereof. It is also intended that the scope of the present invention be defined by the claims appended thereto.