US2763215A

US2763215A - Torque converters

Info

Publication number: US2763215A
Application number: US263318A
Authority: US
Inventors: Herbert L Misch
Original assignee: Studebaker Packard Corp
Current assignee: Studebaker Packard Corp
Priority date: 1951-12-26
Filing date: 1951-12-26
Publication date: 1956-09-18
Anticipated expiration: 1973-09-18

Description

Sept. 18, 1956 H. L. MISCH TORQUE CONVERTERS &

Filed Dec. 26, 1951 I INVEINTOR.

HERBERT MlSCH ATTORNEYS.

TORQUE CONVERTERS Herbert L. Misch, Royal Oak, Mich., assignor to Stude- This invention relates to composite metal structures and more particularly to an article and method of forming such article from steel and aluminum parts.

For purposes of illustration merely, this invention will be described with reference to its application in connection with one of the elements of a hydraulic vane tape torque converter, it being understood, however, that the invention can be adapted for use with other devices as well.

In such fluid coupling devices, for example, the pump element of the torque converter is usually constructed in in such form as to serve as a portion of the housing for the converter. The vanes themselves are disposed generally radially in the housing and they are centered approximately axially with respect to the outer and inner edges of the housing element. In the form of the invention here shown, the overhanging outer and inner portions of the housing serve to enclose the turbine and other parts of the torque converter structure which parts are disposed in the space which extends from the ends of the vanes and the flywheel of the engine to which the pump element of the converter is secured on the one hand, to the other ends of the vanes and the output shaft of the converter on the other hand.

This forms a complicated pump element structure which includes the vanes themselves that are of a rather complex form and contour to enable them to energize the fluid in the converter with maximum efiiciency. A

commonly used method of forming such a pump element of a converter is by casting the vaned element and the housing integral, the material used being generally aluminum, or some lightweight alloy of aluminum, to reduce the mass of the element and its rotational moment of inertia.

It is also apparent that when the unit is cast as one piece, a more complex molding operation is involved and that the rough casting presents a more difficult problem when it is necessary to remove rough spots from the surfaces of the vanes and burrs from the edges of the fluid flow passages. It should be noted too that a single casting of aluminum must be somewhat large or relatively bulky in order to provide the necessary strength and that sometimes castings are malformed to such an extent as to be porous. It is therefore desirable to minimize the casting operation and yet provide a way of constructing a complex shape having a relatively light weight yet strong and compact form.

The principal object of this invention is to provide an article of complex form, such as a vaned pump or turbine element for a torque converter or the like, which will have cast vanes of lightweight nonferous materiaLbut which may be assembled by being welded to a steel housing. The composite structure may thus be completed in a manner to greatly reduce the cost of the final product so as to make it much less expensive than similar elements generally available at present.

Another object of this invention is to provide an article such as a vaned pump or turbine element of a torque con- Patented Sept. 18, 1956 2 verter wherein the vanes are cast of aluminum or its alloys and the outer shell is a steel stamping, with improved means for fixedly securing the cast vanes to the stamping.

A more specific object of this invention is to provide a method and means for securing an aluminum casting to a stamped steel housing wherein the casting is mechanically locked to the stamping, the locking means itself being a steel stamping that may be welded to the housing. In one embodiment thereof, the locking means may include; one or more steel stampings inserted into grooves in the casting and having tabs which abut on the casting, the tabs being spot-welded to the housing to hold the casting in place. In another modification, the steel locking means is shaped like a hoop and has inwardly pressed projections around which the aluminum casting is poured to secure an integral mechanical lock between the hoop and casting. The hoop may then be welded to the stamped steel housing.

Another object of this invention is to provide a method of forming composite articles having cooperating locking means for joining together a cast portion which is made of a non-weldable material and a stamped portion of an other material that may be welded.

In addition to the above, other objects will appear more fully in the specification below.

The preferred form of the invention is shown in the drawings forming a part of this specification, however, it is to be understood that the invention is not to be limited to the details of construction and arrangements of parts here shown, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description only and not by way of limitation.

In the drawings:

Figure 1 is a perspective view showing a composite torque converter pump structure embodying the principles of this invention;

Figure 2 is a quarter-sectional view of the element of a torque converter shown in Figure 1;

Figure 3 is a plan view partly broken away showing the periphery of the cast vaned element of Figure 1;

Figure 4 is a view taken along line 44 of Figure 2;

Figure 5 is a fragmentary section through a modified form of this invention;

Figure 6 is a plan view of the modified locking element shown in Figure 5;

Figure 7 is a section taken along line 77 of Figure 5; and

Figure 8 is a fragmentary section through still another modification of the invention.

Referring now to the drawings for a detailed description of the invention and particularly to Figures 1 and 2, the vaned pump element of the torque converter made in accordance with this invention is formed of a cast aluminum or aluminum alloy element 10 and a stamped steel shell 11, the latter extending around the cast aluminum portion and axially beyond as at 12 to house other elements of the converter such as the turbine element 13, and to provide a means for attaching the torque converter pump means to a flywheel or other driving means (not shown). The stamped shell 11 also extends radially inward as at 14 to cooperate with or have a bearing contact with an output shaft (not shown), to complete the space within which the operating fluid for the converter is confined.

At the extreme right of the housing as viewed in Figure 2, a flat surface 15 is formed on the casting 10, which as hereinafter described functions to assist in locating the casting in the housing 11. Between flat surface 15 and the inward portion 14 of the housing, a shoulder 16 is provided in the housing, which acts as a centering means .housing are subjected to the welding operation.

taking the form of an annular seat for locating the aluminum casting in the housing.

The vanes 17 of the pump element may have any desired shape and for maximum efliciency in a torque converter, vanes 17 are not only curved, .but also vary in thickness, which shape makes it quite difficultto form them by any operation other than by casting. Vanes 17 are held in spaced relation radially aboutcasting by an outer shell 18 and an inner shroud 19, both of which are cast integrally with vanes 17. The shell 18 is finished so as to have a generally flat outer periphery or flange 20, and the shell also has an inner bead 21 having an inwardly facing cylindrical surface 22 formed thereon which fits snugly on shoulder 16 to center casting It in stamping 11.

It is apparent from an inspection of Figures 1 and 2, that it would be difficult to make the entire pump element as a single casting. This is particularly true when aluminum is used, as is customary, to reduce the mass and rotational inertia of the element. In this case, the increased quantity of aluminum needed adds to the cost of the element, and also the cost is increased because of the required cleaning up and machining of the casting. The very size and complexity of such a casting would make the mold relatively expensive, and would greatly add to the difliculty of cleaning up the rough portions of the casting and particularly the working surfaces of the vanes, the shell 18, and inner shroud 19. The advantages inherent in limiting the casting operation to merely the vaned portion of the pump element are thus obvious.

In following the teaching of this invention, the aluminum vanes, and only as much of the pump shell and shroud as are necessary to support the vanes, are cast together as a unit. The remainder of the pump housing is formed of any other material which may be relatively inexpensive and which lends itself to a stamping operation, such as steel. It is essential, however, that the vaned casting be fixedly joined to the stamping without piercing it whereby to minimize the possibility of leaks forming through which the hydraulic fluid might pass in escaping from the converter.

One form of a means which may be used for so attaching the casting to the housing 11 is shown in Figures 1 to 4 to which reference is now made. In this form of the invention, the flange 20 at the periphery of the casting has the spaced axially disposed grooves 23 machined therein, the sides 24 of which are disposed at right angles with respect to the floor of each of their respective grooves, as shown in Figure 4. Said grooves 23 are designed to cooperate with the T-shaped steel inserts 25, by receiving the tail portions 26 thereof while the cross bars 27 are adapted to be fitted snugly against flange 29 as shown in Figures 1 and 2. The edges of each of the tail portions 26 are rectangularly shaped so as to closely fit into grooves 23. The T inserts 25 may be and preferably are made as stampings, which may be further machined, if necessary, to provide a snug fit in grooves 23.

In making use of this form of the invention, the cast aluminum pump element 10 is temporarily pressed into the annular seat formed in the stamped steel shell 11, and the inserts 25 are then placed in grooves 23 to form an assembly. After the inserts are all in place, the protruding cross bars 27 of each of the T-shaped locking members are spot-welded or otherwise integrally secured to shell 11. The cast element 10 is held in the stamping so that the flat surface abuts the rear wall thereof and the inner cylindrical surface 22 is centered on shoulder 16 whereby the cast part is properly located in shell 11 to hold it fixed during the welding operation. During performance of the spot welding operation, care must be exercised to press cross bars 27 against the front side of flange and it is desirable that axial pressure be exerted on the cross bars during the welding operation so that the cast portion 10 will be tightly engaged against the stamped shell 11 when the juxtaposed cross bars and the It is 4 most important in the case of a torque converter that the pump element be fixed tightly in place to avoid all rattles and other possible sources of noise in the finished product.

The number of T locking inserts needed depends upon the forces involved and the strength of the materials used. To preserve dynamic balance, and to minimize weight, the use of a minimum number of two diametrically opposed inserts is preferred, but any number of inserts may be provided to complete the assembly, as long as it is dynamically balanced upon the completion thereof.

In one welding method it is possible to weld two juxtaposed pieces of metal together without having both pieces contacted by the welding electrodes. This welding method can best be performed in connection with the alternative designs of welding strips adapted for use in a torque converter element, which strips are shown in Figures 5 to 8 inclusive, to which reference is now made.

The same form of steel shell may be used and a cast aluminum vaned portion 30 is formed which is generally similar to the vaned element 10, except that its outer periphery or flange 31 is not axially grooved. Instead, a steel ring, or hoop, 32 is cast integral with the flange 31, said ring having angularly disposed tabs 33 punched inwardly at regular intervals. Ring 32 may be initially placed in the mold during the casting of the vaned pump element 30, and the material from which the casting is being made will flow around tabs 33 thus locking the ring mechanically to the casting as shown in Figures 5, 7 and 8.

After the completed casting 30 is removed from the mold and suitably cleaned, it may be pressed into the annular seat provided in housing 11 as explained above, and the housing 11 may then be welded to ring 32 by the aforesaid welding technique. Since tabs 33 are embedded in the cast portion 30 it is not necessary, in this instance, to take any special precautions such as to press the pump member axially inwardly relative to the casting during the welding operation. The composite vaned structure should however be firmly and concentrically seated within the shell during performance of this welding operation.

A further modification of the invention is shown in Figure 8, wherein a ring 34 is disclosed as being cast integral with the pump element 30. Ring 34 may be formed generally like ring 32 except that it is wider and overhangs the periphery of flange 31 of the vaned casting as shown at 36. The overhanging portion may then be welded directly to housing 11 in the same manner as described in connection with inserts 25, or ring 32.

The composite article, formed in the manner outlined above, makes use of a steel housing 11 which is leakproof together with a rigidly mounted, lightweight, and relatively inexpensive vaned pump element. The preferred form of the invention has been disclosed in connection with the construction of a torque converter pump but it is obvious that it can be used in fabricating many similar composite structures where the factors of relatively light weight, strength, and compactness are important. In making use of this teaching the most desirable material for each of the several parts of the composite structure may be selected in accordance with the optimum specifications therefor, and all of the parts may then be subsequently assembled as here taught.

It is thus to be understood that the foregoing description is merely illustrative of a preferred embodiment of this invention and that various other forms thereof may be conceived, without departing from the spirit and scope of the invention, as set forth in the following claims.

What is claimed is:

l. A composite structure such as the pump element of a torque converter or the like formed of a ring-like steel housing having an interfitting ring-like vaned aluminum casting, the two metals being incompatible from a welding standpoint, said housing having an annular space formed therein to receive said casting, said casting having axially disposedslots cut therein at spaced points around its outer periphery, said casting being adapted to be pressed into said annular space with its periphery in contact with said housing, a plurality of T-shaped steel locking means one of which is adapted to be engaged in each of said slots with the tail of the T in the slot and the cross of the T abutting the periphery of said casting, said locking means being compatible from a Welding standpoint with said housing, the cross of said T-shaped piece being positioned with respect to said casting and said housing to overlay a portion of said housing, and welded joint means between each of the said cross parts of the T-shaped pieces and said housing to hold said composite structure assembled.

2. A composite structure such as the pump element of a torque converter or the like formed of a ring-like steel housing having an interfitting ring-like vaned aluminum casting, the two metals being incompatible from a welding standpoint, said housing having an annular space formed therein to receive said casting, said casting being adapted to be pressed into said annular space with its periphery in contact with said housing, steel locking means in the form of a ring cast integral with the outer periphery of said vaned casting, said steel ring overhanging one edge of said casting and being positioned juxtaposed said housing when said housing and casting are interfitted, said locking means being compatible from a welding standpoint with said housing, and welded joint means between the overhanging portion of said compatible locking means and said housing to hold said composite structure assembled.

3. A torque converter or the like, comprising a generally annularly shaped steel housing and an interfitted annular member, the inner portion of said housing being provided with a seating shoulder, said interfitted member being cast of a light weight metal incompatible with said steel housing from a welding standpoint, said annular interfitted member including a plurality of blades cast integral with inner and outer shroud members, one end of said outer shroud being adapted to engage on said seating shoulder when said housing and annular members are interfitted, locking means cooperating with the other end of said outer shroud, said locking means engaging the shroud in a manner to prevent the annular member from having any axial or rotative movement relative to the housing, and said locking means being formed of a material that is compatible from a welding standpoint with the housing and being welded to the housing to hold said annular member immobile and seated within the housing.

References Cited in the file of this patent UNITED STATES PATENTS 1,338,994 Miller May 4, 1920 2,463,581 Welsh Mar. 8, 1949 2,473,185 Weiss June 14, 1949 2,494,539 Bolender Jan. 17, 1950 2,613,609 Buchi Oct. 14, 1952 2,653,547 Langdon Sept. 29, 1953