US3152447A - Impeller assembly - Google Patents

Description

Oct. 13, 1964 M. J. WACLAWEK IMPELLER ASSEMBLY 2 Sheets-Sheet 1 Filed Aug. 21, 1961 Irv/6712 27:

Oct. 13, 1964 Filed Aug. 21, 1961 M. J. WACLAWEK 3,152,447

IMPELLER ASSEMBLY 2 Sheets-Sheet 2 United States Patent 3,152,447 IMPELLER ASSEMBLY Miczyslaw J. Waclawek, Olympia Fields, 111., assignor to Borg-Warner Corporation, Chicago, Ill., a corporation of Illinois Filed Aug. 21, 1961, Ser. No. 132,781 1 Claim. (Cl. 60-54) This invention relates to hydrodynamic couplings and more particularly to a vaned impeller assembly forming part of the hydrodynamic coupling.

Heretofore, difliculty has been experienced in retaining vanes or blades in operative position in high torque impeller assemblies. conventionally, the vanes or blades have been formed at their outer edges with tabs which are received in registering slots at the impeller shell. The inner edges of the vanes or blades have been formed with tabs for reception in registering openings in a shroud ring and bent over to grasp the ring. By this arrangement, the shroud ring was retained in an operative position and the vanes or blades were evenly spaced each from the other. No positive means other than the vanes or blades themselves have been used to assure retention of the shroud ring in a positive position with respect to the shell.

Other methods of fastening the vanes to the shells have included clenching preformed teeth on the vanes into the relatively soft surface of the shell, or Welding portions of the vanes to the adjacent shroud ring or shell. Each of these methods presented severe difliculties when applied to high torque impeller assemblies. For example, the welding of the vanes to the housing provides too rigid a connection therebetween without permitting a certain amount of flexure to the shell and shroud ring to accommodate the high fluid pressures therein.

A primary object of this invention is to provide a hydrodynamic coupling having positive means for retaining an impeller, shroud ring and the several impeller blades or vanes in proper position and lateral alignment.

A further object of this invention is to provide a vaned element for a hydrodynamic coupling such as a torque converter or the like, in accordance with the preceding object, wherein the positive securing means may be employed without requiring changes in tooling in the manufacture thereof and wherein the efliciency of the fluid movement within the vaned element is substantially unaffected.

Another object of this invention is to provide a vaned element for a hydrodynamic coupling device wherein a plurality of circumferentially spaced socket portions are provided on one of spaced shell members thereof and cap screws are adapted to engage the other of said shell members while being threadably received in a socket portion. A particular feature of this object is the ability of the cap screws and cooperating socket to cause the shell members to apply compressive stresses to the edges of said vanes whereby the conventional interengaging tabs and slots of the parts may be maintained in their usual engaging condition in spite of high operating pressures.

Still another object of this invention is to provide a vaned element of a hydrodynamic coupling device in which independent positive securing means isemployed to maintain said vanes in proper lateral alignment under all operating conditions, and which is particularly adapted for ease of assembly during manufacture and is adapted to be both economical and reduce repair costs.

The invention consists of novel construction, arrangements and devices to be hereinafter described in claims for carrying out the above stated objects, and such other objects as will appear in the following description of certain typical embodiments of the invention illustrated in the accompanying drawings, wherein:

FIG. 1 is a central sectional and elevational view of a drive mechanism including a torque converter and embodying the principles of this invention;

FIG. 2 is a fragmentary side view of the construction of FIG. 1 and is taken substantially along line 22 as shown in FIG. 1;

FIG. 3 is an enlarged fragmentary view of the impeller taken substantially along line 33 of FIG. 1;

FIG. 4 is a fragmentary view taken substantially along line 1-4 of FIG. 3;

FIG. 5 is a view similar to that of FIG. 3 and illustrating a modified form of the present invention;

FIG. 6 is still another view similar to that of view 3 and illustrating another modified form of the present invention.

Referring to the drawings and more particularly to FIG. 1, the invention is illustrated as embodied in a drive mechanism rotatable about an axis AA and operable to transmit drive between an engine crank shaft (no-t shown) and a transmission input shaft 10. The drive mechanism comprises a torque converter generally indicated at 11 and operably connected between the engine crank shaft and the transmission input shaft 10. The torque converter generally has a housing 12 consisting of front and rear sections 13 and 14, each having peripheral flanges 13a and 14a respectively adapted to be secured together so that the sections may define a fluid chamber 15 within which is operatively contained fluid driving and reaction elements of the torque converter.

The front section 13 more particularly comprises a substantially dished-out member or stamping of sheet metal, such as steel, having a major radially extending portion 17 which is semi-toroidally shaped; the radially inner extent of the major portion 17 has an annular flat hub portion 13 provided with a central opening 18a therein. A bearing member 19 is fastened to the marginal portion of the hub about the central opening 13a and is in general alignment with the opening; the fastening may be accomplished by suitable industrial adhesives such as a continuous line of welding, as at 19a. The outer extent of the major portion has the radially extending integral flange 13a containing a plurality of circumferentially spaced openings 21.

The rear section 14 of the torque converter housing more particularly comprises a cast member of aluminum or the like, and has a major portion 22 forming the outer shell of an impeller for the torque converter; the portion is substantially semi-toroidal in shape having an annular flange 23 at its radially inner extent and adapted to be fastened to a radially extending flange 24 at one end of a sleeve shaft 25 by a plurality of fasteners 26. The radial outer extent of portion 22 comprises an axially extending cylindrical portion 27 carrying flange 14a at its terminal end and the flange 14a has a plurality of circumferentially spaced openings 27 provided therein, in alignment with the openings of flange 13a. Suitable bolts 28 are adapted to be received in said openings for securing said flanges together.

More particularly, the driving and reaction elements contained within the housing of the torque converter comprise a turbine'3tl, a stator 31 and vanes 32 cooperating with the portion on outer shell 22 to constitute an impeller 33. The turbine 30 is drivingly connected to the input shaft It) for the transmission. A one way clutch device 34 is disposed between an intermediate shaft 35 and the stator 31; the one way clutch may be of any suitable construction and in the illustrated embodiment comprises an inner cylindrical race 36, an outer cylindrical race 37 and a plurality of tiltable sprags 38 between the races.

The hydraulic torque converter functions to multiply the torque between the crank shaft and the transmission input shaft 10, all of the converter elements having blades provided with shapes such that they are capable of providing a toroidal circulation of fluid, whereby the vanes of the impeller 33 impart energy to a body of fluid Within the converter and the turbine 38 receives the energy of the fluid, the stator 31 having vanes 39 cooperating with vanes 32 and 40 of the impeller and turbine respectively and having a reaction force impressed thereon by the fluid, the vanes of the converter elements being etfective, when the stator is held from rotation by the one way clutch 34 to serve as a reaction element, to change the direction of flow of the fluid so that the converter multiplies torque.

Turning now more particularly to the construction of the impeller, the substantially semi-toroidal portion 22 forming the outer shell of the impeller has a plurality of recesses or receptacles 45 provided in the inner surface thereof, arranged generally in rings (FIG. 2) each ring having said recesses circumferentially spaced apart. Spaced from the inner surface of the semi-toroidal shell member is a shroud or core ring 46 forming an inner shell member for the impeller and is substantially semi-toroidal in shape. The core ring has a plurality of slots 47 provided therein and arranged in rings, each ring having the slots circumferentially spaced. Disposed between the shroud and impeller outer shell is the plurality of relatively thin vanes 32 having opposite edges 48 and 49 engaged by the outer shell and shroud ring respectively. Said edges are arcuately shaped so as to mate with the interior surfaces of the shroud ring and outer shell and have provided thereon at such edges or marginal portions a plurality of tabs or projections 51, certain projections of which are adapted to be received in the recesses of the impeller outer shell and others of which are adapted to be received by the slots of the shroud ring.

It is quite important to maintain a predetermined spacing between the outer shell of the impeller and that of the shroud ring during all operational conditions of the converter. Heretofore, the positioning of the vanes has always been assured during such conditions by the interlocking eifect of the projections received within the outer shell recesses and accompanied by the effect of the tabs extending through the shroud ring slots and tab ends clinched against the side thereof. Such fastening means were suflicient to prevent unwanted lateral movement of the vanes since the experienced pressure forces caused no substantial deviation in spacing of the shroud ring from the outer shell of the impeller during operation.

In response to the desire for higher stall K factors in the design of torque converters of today, severe high pressure conditions are now encountered by the vaned elements such as the impeller. Particularly where the impeller shell is constructed of sheet metal, such high pressures during operation have a tendency to flex and flatten out the impeller outer shell as well as the shroud ring during operation. Such distortion of the impeller walls may cause the tabs or projections on the outer arcuate edges of the vanes to withdraw from the recesses within the impeller outer shell or slots in the shroud ring and thereby permit the vanes to become dislocated, resulting in severe damage to the impeller. Under conventional constructions, failures due to dislocation of the vanes have been encountered at 200 ft.-lbs. of torque. Such limitation is not adequate to meet the requirements of modernday designs.

To obviate the above problems and yet to retain the condition of a relatively flexible impeller construction, the present invention contemplates provision of an independent fastening means which is adapted to cause the shroud ring and impeller outer shell to apply a compressive stress to the outer edges of the vane whereby the interengagement of the tabs and recesses or slots is assured regardless of internal fluid forces.

As shown in FIG. 3, the outer shell of the impeller is provided with three circumferentially arranged socket portions 60 adapted to extend axially thereof. Each of the socket portions 60 contains a threaded bore 60a which faces toward the shroud ring (the preferred embodiment is here shown to comprise three equi-distantly arranged socket portions but it is contemplated that two or more may be utilized). The socket portions are located substantially near the intermediate portion of the semitoroidal curvature of the impeller outer shell.

A plurality of cap screws 62 are adapted to be inserted through openings 63 provided in the shroud ring and aligned with the socket bores 60a; each of the cap screws have one end which is adapted to be threadably received by the threaded bores 60a of the socket portions and have an opposite end carrying a head 62a which is adapted to engage one side of a retainer plate 64 which is substantially flat in shape and has at least opposite ends 65 and 66 thereof engaging the inner contours of the shroud ring. The retainer plate 64 may be constructed of heavy duty sheet metal and as shown in FIG. 4, has cut out portions 64a adapted so that it will not interfere or engage the fastening tabs of the vanes.

Since the cap screws will be subject to vibrational forces tending to loosen them, means must be provided to secure them Within their sockets and prevent their unscrewing during operation. A preferred construction, pursuant to this end, is illustrated in FIG. 3 wherein a lock washer 67 is sandwiched between the retainer plate 64 and the cap screw head 62a to prevent turning of the cap screw and is used in conjunction with a screw-thread bonding applied to the threaded end of the cap screw, such as Loctite.

An alternative embodiment of the independent interengaging means between the shroud ring and impeller outer shell may comprise that shown in FIG. 5 in which the cap screw is inserted in the socket portions similar to that of the preferred embodiment but in place of the retainer plate and the lock washer is provided a localized application of welding 70 to secure the head of the cap screw to a specially preformed flat area 71 of the shroud ring. In the embodiment of FIG. 5, the inner face of the cap screw head fits flush against the flattened area 71 of the shroud ring. The embodiment of FIG. 6 is similar to that of FIG. 5 except that in place of the local welding, the flattened areas of the shroud ring are each provided with one or more tangs 73 stamped from the shroud ring and bent upward to resiliently engage a side of the cap screw head and thereby provide a spring tension for preventing loosening of the cap screws during operation.

Each of the above embodiments are illustrated with the shank 62b of the cap screws extending through a generally central portion of the path of circulating fluid; the presence of the cap screw shanks offer very little interference with the toroidal fluid flow therethrough and can be disregarded for most design characteristics. The present invention provides a highly economical and easily adaptable means for insuring retention of the vanes in proper alignment throughout all operating conditions while retaining the simplicity of sheet metal construction heretofore found most desirable in making the shroud ring and vanes.

While the preferred embodiments of the present invention have been shown and described herein, it is obvious that many structural details may be changed without departing from the spirit and scope of the appended claim.

I claim:

In a hydrodynamic coupling, an impeller assembly, comprising: a hollow, substantially semi-toroidal housing having a plurality of slots both radially and circumferentially spaced; a semi-toroidal shroud in said housing and spaced from the interior wall thereof and having a plurality of openings extending therethrough and spaced radially and circumferentially thereof; a plurality of thin vanes having arcuate inner and outer edges meeting with the inner surfaces of said housing and the shroud respectively, said vane edges having tabs projecting outwardly therefrom, said tabs on one edge fitting within said slots and extending outwardly therefrom to engage the housing side, and other of said tabs extending through the openings in said shroud and engage the opposite side of said shroud, said housing having a greater thickness than said shroud and said housing having formed thereon a plurality of threaded socket portions facing the interior of the housing; a plurality of cap screws contained wholly within the shell outer surface having one end extending through openings in said shroud and engaging the opposite side thereof, the other end of said cap screw being threadably received by a socket portion in said housing in a manner to draw the shroud and housing together to apply compressive stresses to the edges of said vanes for preventing disalignment of said vanes under all operating conditions; and locking means associated with said shroud and cap screws to prevent turning of the screws during operation of the coupling, said locking means comprising a resilient retainer plate for each of said cap screws and disposed chordally of said shroud, each retainer plate having opposite edges in engagement with the shroud and imparting a resilient locking force against said screws.

References Cited in the file of this patent UNITED STATES PATENTS 2,371,588 Salerni Mar. 13, 1945 2,371,589 Salerni Mar. 13, 1945 2,692,562 Zeidler Oct. 26, 1954 2,998,782 Ryan et a1. Sept. 5, 1961

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