US2948226A

US2948226A - Hydrodynamic coupling

Info

Publication number: US2948226A
Application number: US511591A
Authority: US
Inventors: Richard L Smirl
Original assignee: Borg Warner Corp
Current assignee: Borg Warner Corp
Priority date: 1955-05-27
Filing date: 1955-05-27
Publication date: 1960-08-09
Anticipated expiration: 1977-08-09

Description

Aug. 9, 1960 R. L. sMlRL HYDRODYNAMIC couPLING 2 Sheets-Sheet 1 Filed May 27, 1955 w wx W/W bw wm qu bw N uw NN .nvm NM. nu 0N .WW Knr. ww l 1- NN i I f@ Q 2 o MN WN -..1| Inu QN QN MN mw .nw Q mn Nw .1Q u hw Q n mm. uw hw, uw K .QN u, um. Sw i .f w l NN QN NN N.

Aug- 9, 1960 R. L. sMlRL 2,948,226

HYDRODYNAMIC COUPLING Filed May 27, 1955 2 Sheets-Sheet 2 United States Patent .HYDRoDYNAMIc coUrLrNG Richard L. Smirl, La Grange Park, lll., assignor to'Borg- Warner Corporation, Chicago, Ill., a corporation of Illinois Filed May 27, 195s, ser. No. 511,591

2 Claims. (Cl. 10S- 115) This invention relates to hydrodynamic coupling devices and more particularly to vaned elements of such devices and a method and apparatus of fabricating or assembling the same.

In prior vaned' hydrodynamic coupling elements, the vanes have been assembled with their supporting members, such as semi-toroidal shells or housings, by positioning the vanesin the housing separately and welding the vanes individually or collectively to the housing; or by clinching over tabs on the vanes extending through slots in the housing; or flexing each vane to position its tabs within slots" in the housing and releasing the ilexed vane to engage the'edges of the slot, followed by a tab clinching or vane-staking operation to insure retention of the vanes in the housing. Any of these arrangements require expensive equipment and consumption of consid-A erableD time and labor to assemble the vanes and housing.

It has been observed that, in the use of such vaned coupling elements with the progressively higher engine speed now conventionally the trend in automotive vehicles, the vanes must not only be mechanicallyinterlodked with the shell, but the vanek and shell Iassembly must be subjected to a brazing operation to insure'the vanes are retained in the shell. These multiple assembly operations are necessary due to the. hydrodynamic pressure forces acting on the semi-toroidal shell and tending to distort the-shell by suiliciently axially deflecting or ballooning the'shell to disrupt the vanes disposition with respect to the shell and loosening or dislodging the vanes from the shell. Axial deflection of the shell ofthese vaned elements also presents a problem to the correct Gee to carry the hydrodynamic yforces unaided, it is possible to preload the shell suiiiciently, within its elastic limit, to take advantage of the stilness of the vanes in the assembly to reduce axial deection of the shell to a negligible quantity'and to insure the vanes being securely held by the shellV at high engine speeds, for example, such as 4000 r.p.m.

Another object of the present invention is to simplify the construction and arrangement of a hydrodynamic coupling element, and to provide an improved method of assembling the respective parts thereof.

Another object ofy the invention is to provide an improved hydrodynamic'coupling element assembly in which the parts thereof may be quickly and satisfactorily conoperation of thehydrodynamic coupling device' as the t vice, `and an'undesirable amount of axial deflection of the impeller shell causes the'pump gears to jam.`

The' primary object `of the invention to provide an improved hydrodynamic coupling element and method of making the same in which the coupling element com"- prises` ahollow shell preferably in the form of a substantially serni-toroidal stamping of sheet metal,I such as steel, and a plurality of vanes, preferably of sheet metal, such as steel, having portions interengageable with portions of the shell to provide a mechanical interlock `with the shell, thel invention being particularly characterized by the shell being flexed by pressure'suiicient to expand the shell within its elastic limit to provide a considerable contractive Vforce of the shell, when the pressure is released, aiording a preloading of the shell toV lrmly'engage the vane portions with the shell portions, and, as the vanes are disposed radially of theshell and in annular varray vwithin the shell, thevanes have a rigidity capable of withstanding the contractive force of the 'preloaded shell without bending or distorting the original shapes pf the vanes. Since the shell has sufficient yield strength nected together with the necessary strength vto withstand the hydraulic forces encountered in operation at high engine speeds. i

Another object of the invention is to provide an improved hydrodynamic coupling element and method of assembling the same in which a semi-torcidal sheet steel housing has slotsV therein and is capable of expanding to receive vprojections on the vanes in the slots and contracting to engage the projections with the housing with sufficient force to positively interlock and securely hold the vanes inthe housing.4

It is, a further object of the invention to provide an improved hydrodynamic coupling element and method of assembling the same which may include a hollow housing of any metal capable 'ofexpanding and contractingto position vanes of sheet metal, or cast metal, having portions Vthereof fitted into recesses in the housing and engaging the'housing edges delning the recesses.

' Another object of'the'invention is to provide a hydrodynamic coupling ele'ment'as described wherein the vanes may be formed of a rigid material andincapable of ex'- ing and distorting in assembly with the shell to insure the maintenance of the desired shape of Ythe vanes in the completed assembly.

A further object of the invention is to provide an improved hydrodynamic coupling element and method of assembly thereof in which a hollow llexible housing is provided with a semi-torcidal surface having slots therein and tabs on the vanes' extend from the arcuate margins thereof; which margins are of less curvature than the surface of the housing, the housing being ilexed to expand the same to decrease'the curvature of the surface thereof to permit engagement of the arcuate margins of the vanes yand positioning ofthe vane tabs in the housing slots; the shell then being allowed to contract to forcibly engage the vane edges with the housing slotedges and to continue to exert a contractive force to hold the vanes and housing in assembly. A further object of the invention is to provide a new and hydrodynamic coupling element assembly apparatus for placing and securing the vanes and housing together.

' AdditionalV objects, aims and advantages of the invention will' be apparent to persons skilled in the art from a consideration of the construction and assembly of the hydrodynamic coupling element and its method of assembly and apparatus for assembling as contemplated in the within description, and in the accompanying` drawing in which: n

Fig. 1 is an axial sectional view of a hydrodynamic coupling element' and the preferred form of apparatus, such as a press, for connecting a plurality of vanes to the hollow shell ofthe element, and illustrating the shelland vanes being'A positioned for assembly in the press andprior to the assembling operation;

Fig. 2 is a fragmentary axial sectional view showing the press completely closed; and

Fig.Y 3 is afragmentary axial sectional view showing the press open, and the vanes and shell in assembled condition; and

Fig. 4 is a view similar to Fig. 2 illustrating the press in closed position and in use with a shell shallower than that shown in Fig. l.

The drawing is to be understood as being more or less of a schematic character for the purpose of disclosing typical or preferred forms of the'improvements which are contemplated herein, and in this drawing like reference characters identify the same parts in the diiferent views.

Referring to the drawing, the improved hydraulic torque converter vaned element is generally indicated at and comprises a semi-toroidal annular shell or housing 11 which may be stamped sheet metal and capable of expanding and contracting. The shell has its radially inner periphery defined by a flat hub portion 12 for piloting the element on a shaft, or the like, for rotation about its axis indicated by the line A-A in Fig. l. The shell 11 is provided with a plurality of vanes 13 positioned within the semi-toroidal shell 11 and connected to the shell and a core ring 14 of semi-toroidal shape, as shown more particularly in Fig. 3, to provide the hydraulic torque converter vaned element. The vaned element 10 is in its preferred embodiment illustrated as an impeller of a hydraulic torque converter, which in conventional practice, also includes a turbine and a stator for providing a closed toroidal circuit for the circulation of iluid through the irnpeller, turbine, and stator, the vanes of the impeller, turbine, and stator having curvatures designed to provide infinitely variable torque ratios from the stall condition and to the coupling range of the torque converter, when the stator is held stationary, as it is well known in the hydraulic torque converter art.

Fig. 3 illustrates the shell, vanes and core ring in assembly, the shell 11 being provided with radially spaced elongate openings, recesses, or slots 15 and 16 in its semitoroidal surface 17 respectively receiving

tabs

18 and 19 formed on the arcuate outer edges of the vanes, the shell being further provided with a plurality of radially spaced sets of V-shaped openings, recesses, or notches 21 and 22, with one set of notches 21 being disposed between the slots 15 and 16, and the other set of notches 22 being disposed radially inwardly of the slot 16, these sets of notches 21 and 22 receiving pairs of V-shaped tabs or teeth on the arcuate outer margin 20 of the vane.

A feature of the present invention resides in the shell 11 being composed of a metal capable, when stamped into the form of the shell, to flex suiciently to expand and contract; the semi-torcidal surface of the shell being formed with a curvature greater than the curvature of the arcuate outer margins or edges of the vanes and, accordingly, the radius of curvature of the shell surface being less than that of the vane edges; and the vanes being rigid in an axial direction and being restrained laterally by tabs engaging slots in the shell 11 and core ring 14. It will be apparent that the free curvature of the shell and the spacing between the outer slot 18 and inner slots 24 may be controlled to provide an interference or preloaded iit with the vanes. Furthermore, it is contemplated that pressure be applied to the shell to cause it to expand suiciently to decrease the curvature of the semitoroidal surface thereof to permit the alignment and positioning of the vane tabs in the notches and slots in the shell, and the positioning of the core ring 14 over the tabs and 26 and thereafter to remove the pressure to allow the shell to contract to engage the outer arcuate margins of the vanes with the semi-toroidal surface of the shell and to tightly engage the vane tabs with the edges of the slots and notches in the shell with sucient force to positively interlock and securely hold the vanes in the housing.

.hub 12 is moved axially by the application of force to the hub to expand the shell and to cause the curvature of the semi-toroidal surface 17 to be decreased to less than the curvature of the arcuate margins 20 of the vanes 13, i.e., the radius of curvature of the surface 17 is increased to be greater than the radius of curvature of the arcuate margins of the vanes 1'3. Prior to applying force to the hub 12 of the shell, the vanes may be inserted in the shell and held in the shell, which may be by any suitable slotted locating plate receiving Vthe vanes, with the vane tabs 18 positioned in the slots 15 of the shell, and it will be noted that, in Fig, l, the curvature of the surface 17 of the shell radially spaces the notches and slots in relation to the

tabs

23, 19 and 24 on the vanes to prevent entry of the tabs in the notches 21 and 22 and slot 16 and also the surface 17 of the shell is spaced from the outer margins 2 0 of the vanes. However, as the shell is expanded, the decreased curvature of the surface 17 of the shell allows the tabs to be inserted in the notches 21 and 22 and slot 16, and to engage the surface 17 with the arcuate margins 20 of the vanes. Upon the removal of pressure on the hub 12 of the shell, the shell contracts to force the vane tabs, and particularly the

tabs

18, 23 and 24, into engagement with the edges of the notches and slot 15 in the shell to hold the vanes and shell in assembly and to prevent movement of the vanes axially and radially of the shell. Upon assembly of the shell and vanes as described, the core ring 14 is positioned on the inner arcuate margins of the vanes with the tabs '25 and 26 extending therefrom positioned in slots in the core ring, the

vane tabs

25 and 26 being bent over to engage the inner surface of the core ring to complete the assembly of the impeller.

The housing 11 and vanes 13 are assembled by the apparatus and in the manner shown in Figs. 1,2 and 3. The apparatus employed for fixing the vanes in the housing comprises an arrangement whereby the vane tabs k18 are positioned in the slots 15 to dispose the vanes in proper More particularly and referring to the drawing, the

radial array and equidistantly spaced from each other and the hub 12 of the shell is then forced downwardly and along the axis A--A of rotation of the vaned element to cause the curvature of the surface 17 of the shell to decrease so that the remaining tabs of the vanes may be inserted within the notches and slot 16 in the shell, the pressure on the hub 12 of the shell then being removed to allow movement outwardly and upwardly of the shell 12, along the. axis of the shell to provide forces in the shell attempting to return the surface 17 of the shell to its initial curvature but being restrained by the tabs tightly engaging the ends of the slots and notches in the shell and securely holding the vanes in the shell.

More particularly, the apparatus for assembling the vanes with the shell comprises a press having an annular bedplate 27 mounted on a stationary support 41 and provided-with an inner semi-toroidal surface 28 of substantially less curvature than the curvature of the shell 11 and terminating at the outer peripheral cylindrical surface 29. at the upper radially outer margin of the bedplate. The radially inner edge or hub 30 of the bedplate is provided with a top flat surface 31 for engagement with a complementary at surface on an oisetportion 32 of the hub 12 of the shell 11, connecting the hub 12 with the semi-toroidal portion of the shelL The pressure member of the press comprises an annular thrust plate 34 located centrallyV of the bedplate and supported on a rod 35 positioned for movement downwardv along an axis corresponding to the axis of the bedplate and the shell, the rod extending through an axial opening in the plate 34 and having, a shoulder 36 engaging the edge of the opening in the plate. The plate is held tightly against the shoulder by a O-shaped washer 37 received Within an annular groove 38 in the rod 35. This assembly of the plate 34, rod 35 and washer 37 causes the plate 34 to move axially on movement of the rod 35. The plate 34 t has a cuplike portion provided by a downwardly extending flange having a at surface 39 engageable with the offset portion 32 of the hub 12 of the shell 11.

The plate 34 may be provided with a plurality of openings O for positioning the plate on the rod and for removing the plate from. the rod on withdrawing the washer from the rod. Y

The thrust plate 34 is movable axiallyof the bedplate 27 and the shell 11 by'a piston 40 located with'a cavity 41 in the bed plateandconnected to the rod 35. The piston'40 is provided with a liptype seal 42 engaging the cylindrical side wall of the cavity and the rod 35 1s surrounded by and engaged with aseal ring 43 to prevent the escape of uid under pressure in Ythe Achamber 44 dened by the piston 40 andthe `side and top walls of the cavity formed in the bedplate 27 upon iuid under pressure iiowing into the chamber through aY port 45 connectedto a pump: (not shown) for actuating the piston 40 downwardly to engage the thrust plate 34 with the shell 11. As this time, a spring 36, having one end received within-the piston 40 and its other end seated on the support 41, is compressed by the'piston and, upon the pressure of the uid being relieved in the chamber 44, the spring will be eifective to move the piston 40 and thereby the plate 34 upwardly away from the shell.

As will be seen from an inspection of Fig. 1, the shell 11 is received within the bedplate 27 and is provided with an outer cylindrical portion 47 connected to the semitoroidal portion of the shell and being formed to provide a shoulder 58 engaging the upper edge of the bedplate to position the axis of the shell in alignment withthe axis of the bedplate. Thus, it will be seen from inspection of Fig. l that the shell 11 only engages the upper edge of the bedplate 27, the hub `12 of the shellnbeing spaced from the bedplate, and 'the' thrust plate V34 being positioned above and'spaoed from the hub 12 of the shell 11. The vanes 13 are then inserted in the shell and placedfin' radial array about the semi-toroidal surface 17 with the-tabs 18 positioned within the slots 15 of the shell and the radially inner end of the Vane defining the end tab 24 being positioned in point contact with the portion of the hub definingV the radially innermost notch 22 of the shell. It will be apparent that, as the slots 15 are elongate and only of suicient width to accommodate the tabs `18 the tabs 18 will be held in the slots"15 t0 maintain the vanes in the shell in the position shown in Fig. l. Referring to Fig. l, the shell hub 12 and the bedplate hub 30 are axially spaced apart, for example, al1-distance of .065 inch. vReferring to Fig. 2, upon movementfof thrustplate'34'downwardly, the surface39 of the anged portion of the thrust plate will engage the adjacent surface of the hub of the shell 11 and move the hub of the shell downwardly to engage the surface 31 of the bedplate 27. As the engagement at 58 of the shell 11 with the bedplate 27 prevents downward movement of the outer peripheral edge of the shell i11, the semitoroidal portion of the shell will move downwardly t0 cause deformation or expansion of the shell in the region X-Y to thereby decrease the curvature of the inner surface 17 of the shell to less than the curvature of the adjacent arcuate margins of the vanes, so that the blades may be moved downwardly, from the position shown in Fig. 2 so as to position the tabs within the slots and notches in the shell as shown in Fig. 3. When the thrust plate is raised clear of the shell as shown in Fig. 3, the exed shell will attempt to contract to regain its original shape as shown in' Fig. 1, but will be prevented from doing so by the vanes having their tabs received within and engaging the edges of the slots and notches in the shell. This will be obvious from inspection of Figs. 1 and 3 wherein the shell in its unexed state, as shown in Fig. l, has .O65 inch clearance between the bottom of the hub of the shell and the top of the hub of the bedplate 27, and in the assembly of Fig. 3, the shell, in attempting to regain its normally unilexed condition, will be prevented by the vanes and remanexed as indicated by the clearance of .040 inch between the hubs of the shell and bedplate. l

It will benoted that the stamped sheet metal or steel vanes ofr a hydraulic torque converter element are provided with accurately calculated and formed shapes to obtain controlleddirectional flow of fluid through the vaned passages Aof the element and determining the torque multiplying characteristics ofthe hydraulic torque converter. These shapesA of thev vanes are critical and in the assembly Ywith the she1l,'it visimperative they be maintainedgas close as possible to their predetermined stamped form for'obtaning the desiredV torque-multiplying characteristicsl-thereof as any variations in the curvatures of the vanes will produce entirely vdifferent torque-multiplying characteristics 'of the vanes. Due to this factor, the vanes -in the present invention are suiciently rigid to prevent bending or deformation in the assembly with the shell and core ring andare `firmly xed and positively held against movement or'displacement. For this purpose, the vanes are iirmlyinterlocked with the shell, when the assembly is completed, by a built-in preload or stress trapped between the vane tabs and the shell'. This advantageous feature minimizes deflections of the shell in operation due to hydrostatic and centrifugal pressures. With the builtin preload, a force greater than thepre-stressed load has to beapplied before any appreciabledeilection takes place in'op'eration, whereas in prior methods of assembly v with the shell not being under any preload or stress, the shell begins deecting with small hydraulic pressures.

After assembling the vanes with the shell las described, the vane tabs 25 vand 26, as shown in Fig. 3, are inserted within the slots Vof the core ring and the tabs are then bent over to engage inner surface of the core ring to cornplete the assembly ofthe impeller, the thrust plate then being raised fromA the assembled vaned element 10.

Fig. 4 illustrates a modification of the invention wherein the shell 47 is formed shallower than the shell 1,1 in Figs. l, 2 and -3 yto obtain the greatest preloading, without exceeding Ythe elastic limit, of the shell and the amount of stretch or expansion for assembly purposes is limited to a point leaving a slight interference at the V-shaped tabs 48 of the vanes 49 with the edges of the notches 50 in the shell 47. More particularly, and referring to Fig. 4, theshell is ilexed by the Iapparatus and the vanes 49 are placed in position in the shell `47, as shown in Fig. 4, and

with the tabs` 48 of the vanes engaging the edges ofthe notches 50 and the vanes are then rapped by a mallet at vtheir inner ends to snap Ythem over the interference provided by. the Vedges of the notches. After the core ring is installed on the vanes in the `manner previously described, the load on the shell by the apparatus is released and a very tightly preload assembly results.

It is within the contemplation of the present invention that the vanes can be of the cast aluminum type having diierent thicknesses throughout the vane, instead of the uniform thickness of sheet metal vanes. Also, the shell should be made of a resilient metal, and preferably sheet steel, which has the ability to be exed or deformed and to attempt to return to its normal shape, or to spring back, upon release of pressure by the apparatus to place the vanes in engagement with the shell with sucient preload or stress to positively interlock the vanes with the shell.

It will be apparent from the foregoing description that va vaned element of a hydrodynamic coupling device, de-

signed and assembled in conformance with the invention, has the advantageous characteristic of providing a signicant reduction in axial deection, or ballooning, of a shell over prior prefabricated and assembled vaned elements, and which feature is of paramount importance in contributing a vane and shell assembly capable of withstanding the hydrodynamic fluid forces resulting in the operation of engines at the high speeds now current in automotive vehicles.

In actual and comparative tests of vaned assemblies;

a cast `aluminum shell and sheet steel V-anes mechanically,

interlocked therewith and in which the shell was pro-, vided with 68 deep external `ribs or fins for maximum rigidity of the shell, the shell had greater axial deflection at 4500 r.p.m. than a preloaded steel assembly with only a f/gg" thickness of the shell. While brazing a mechanically interlocked vane, shell and core-ring lassembly is of value in maintaining the vanev and core ring assembly in contact with the shell during high speed operation, a distinction between the concept of `stiffness as opposed to strength will help visualize how preloading the vane and shell assembly can give the same elect of brazing up to the speed where the preloading force is cancelled by the hydrodynamic fluid forces'. Since the steel shell has sucient yield strength to carry the forces unaided, it is possible to preload sutciently, within the elastic limit of the shell, to take advantage of the stiffness of the vane and core ring Iassembly. For example, if a certain brazed vaned element assembly has .015 deflection at 4000 r.p.m. and if a similar shell, core ring and vane assembly in which the vanes are flexed to engage slots in an unflexed steel shell and are then xed to the shell by deforming edges of the slots in the shell to stake the vanes in the shell, shows -a deilection of .050" at the same speed, the forming the shell of the present invention to give .050" preload in its assembled condition will prevent the shell from moving out of contact with the vane and core ring assembly, and at 4000 r.p.m. only .015 to .020" deflection is found.

In prior vaned elements, the vanes are exed to engage seats or slots in a shell and this assembly method is not easy to apply to flat or substantially at vanes. However, it has been determined that a Vane and shell assembly, produced by practicing the present invention is equally effective with either flat or curved vanes and provides better `deflection characteristics with at vanes than with curved'vanes.

It will be apparent to those skilled in the yart that the invention is also applicable to vaned elements of the fluid coupling of non-torque converting type and it is intended that the expression hydrodynamic coupling device in the claims is intended to cover vaned elements of the torque-converting and non-torque converting type.

lt is to be understood that the expressions openings and recesses in the claims are intended to dene slots or notches. v

While this invention has been described in detail in its present preferred form or embodiment, it will be apparent to persons skilled in the art, after vunderstanding the improvements, that various changes and modiiications may` be made therein without departing from the spirit or scope thereof. It is therefore aimed in the appended claims to cover all such changes and modications.

Iclaim:

1. A vaned element of a hydrodynamic coupling'device comprising a hollow substantially -senni-toroidal flexible housing including an axially facing concave surface normally of a rst radius of curvature, said housing being formed with means dening a plurality of slots; and a plurality of vanes in .said housing respectively provided with convex curved vmarginal portions of a radius of curvature greater than that of said concave portion and generally complementary in contour thereto disposed in engagement with said concave surface, each of ysaid vanes being provided with a plurality of outwardly extending tabs adapted to be received in said slots upon distortion of said housing, whereby said concave surface assumes a radius of curvature greater than said iirst radius of curvature and said housing -is stretched to apply a compressive force to said vane portions so that said vanes are held in tight engagement with said housing.

2. The device dened in claim 1 in which said slots are arranged in circumferentially spaced sets, one of the slots of each set extending substantially axially of said housing and the other said slot of each set extending substantially radially of said housing.

References Cited in the le of this patent UNITED STATES PATENTS 2,304,721 Werther Dec. 8, 1942 2,317,217 Pennington Apr. 20, 1943 2,347,071 Bailey Apr. 18, 1944 `2,360,383 Zeidler Oct. 17, 1944 2,365,354 Pennington Dec. 19, 1944 2,438,867 Rockwell et al Mar. 30, 1948r 2,481,541 Schneider Sept. 13, 1949 2,505,820 Zeidler May 2, 1950 2,542,913 Ensign Feb. 20, 1951 2,576,682 Hall Nov. 27, 1951 2,598,620 Swift May 27, 1952 2,660,957 Koskinen Dec. l, 1953 2,682,703 Schob July 6, 1954 2,692,562 Zeidler Oct. 26, 1954 2,696,171 Jandasek et al Dec. 7, 1-954 FOREIGN PATENTS 4,603 Great Britain of 1905 580,119

Great Britain Aug. 27, 194.6