US2674782A - Method of making oil retainer sleeves - Google Patents

Description

April 13, 1954 sum- 55 2,674,782

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Patented Apr. 13, 1954 OFFICE METHOD OF MAKING OIL RETAINER SLEEVES Robert E. Surtees, Oak Park, Ill. Application June 20, 1951, Serial No. 232,491

4 Claims. 1

The present invention relates to an oil retaining cylinder sleeve for use in internal combustion engines, and to a method of making it. The subject matter of the present invention is an improvement upon the subject matter disclosed in applicants copending application Serial No. 143,697, filed February 11, 1950, and, to some extent, represents improvements over applicants Patent No. 2,361,434.

The principal use of the present invention is in building or rebuilding internal combustion engines. In either case, the desirability of providing replaceable cylinder linings having relatively thin walls is apparent from consideration of the requirement for dissipation of heat developed within the cylinder. While it is possible to make liners from or of seamless tubes, forgings, or castings, the necessity for both the internal and external machining of a preformed rough cylinder blank makes the use of such ablank impractical where wall thicknesses in the neighborhood of .650 inch are desired. Hence, the present invention contemplates the fabrication of a cylindrical sleeve-like member from an original flat sheet of material, the finished member therefore hav ing a seam along a generatrix of the cylinder.

Although both the copending application and the patent mentioned above disclose a liner of generally similar type to that herein contemplated, the present invention provides one that is more quickly and accurately shaped to cylindrical form than either of those previously disclosed. Further, the present invention contemplates the incorporation of surface interruptions or indentations in the interior surface of the liner.

In regard tothese surface indentations, it may be mentioned that it has been found possible to put such a high finish on cylinder walls that a desirable wetting action or capillary attraction of the lubricating oil is eliminated. By incorporating a large number of surface indentations, applicant provides oil retaining wells which, not only maintain a supply of oil adjacent the internal surface of the liners during periods of idleness, but also insure efficient lubrication ,atall engine speeds.

t is an object of the present invention, therefore, to provide a novel cylinder sleeve or liner which is very accurately shaped to a cylindrical form.

It is another objectof the invention to provide a novel cylinder sleeve or liner having aseam along a generatrix of the cylinder which has a superior quality of press ,fit into an engine block.

'It'is another object of'the present invention to provide a novel cylinder sleeve or liner having surface indentations interiorly thereof.

It is another object of the present invention to provide a novel cylinder sleeve or liner having internal surface indentations arranged in predetermined spaced relation one to another.

It is another object of the invention to provide a method for fabricating a cylinder sleeve or liner having a very accurately shaped cylindrical form.

It is another object of the invention to provicie a method for fabricating a cylinder sleeve or liner having internal surface indentations.

Other objects and advantages will appear from the following description taken with the accompanying drawing, in which:

Fig. 1 is a perspective view of a liner constructed in accordance with the present invention;

Fig. 2 is a fragmentary sectional view taken on a diameter thereof showing the liner in an engine block;

Fig. 3 is a diagram indicating the several steps in the preferred method for fabricating the liner;

Fig. 4 is a fragmentary sectional view showing a die'operation for initially forming one end of a strip from-which the liner is made;

Fig.5 is a sectional view of a blank from which the liner is made with the die operation of Fig. 4 having been performed on both of its ends;

Fig. 6 is a schematic view showing the manner of shaping the liner into an intermediate generally cylindrical form;

Fig. .7 isa transverse sectional view of the liner, and indicates a conforming operation in which the liner is shaped very accurately to a cylindrical form;

Fig. 8 is a transverse sectional View of the liner. and indicates a grinding operation on the seam thereof, the parts being exaggerated in proportions for clarity;

Fig. 9 is a plan view of an indented blank showing a preferredpattern of indentations, the spacing between indentations being exaggerated for clarity; and

Fig. 10 isa fragmentary sectional view taken generally along the line |0I0 of Fig. 9, showing a preferred sectional shape of an indentation, the depth of the indentation relative to the thickness of the blank being exaggerated for clarity.

Referring to the drawing more particularly by means of reference numerals, i5 represents generally a cylinder linerconstructed in accordance with theteachings of the present invention. The liner I5 is fabricated .from a fiat sheet of material, as will be hereafter shown. Except for a 3 flared upper edge 16, the liner I5 is cylindrical in shape and has a seam [1 formed by the abutment of ground ends of the original sheet from which it is formed.

The liner i5 is adapted for insertion, usually by a press fit, in an engine block such as 18 in Fig. 2. It will be noted that the flared edge l6 fits into a similarly shaped portion of the engine block IS. The lower end of the liner l5 may be beveled, as at 19, to facilitate its insertion into the block l8.

In general, the steps of the process are those shown in Fig. 3, although it will be understood that under certain circumstances one or more of the steps may be omitted, or they may be performed in a different order.

Desirable materials for the liner of the present invention include well known steel alloys such as Nitralloy, 4130 or 4140, these types being mentioned for illustration and not for limitation. The first step in the process is that shown at I in Fig. 3, and consists of rough-shearing a suitable blank from a coil or straight length of material as received from the rolling-mill source. The width nary rolling-mill is usually somewhat thicker at its center than at its edges, the second step of the process, shown at II in Fig. 3, involves bringing the rough-sheared blank down to a desired uniform thickness. This may be accomplished by either a grinding or a rolling operation, the latter, however, being preferred. Thus, for example, if it is desired to provide a liner having an ultimate wall thickness of .060 inch, a liner blank cut from standard .065 rolling-mill stock may be reduced by step II to a uniform thickness of .0605 plus or minus .0001 inch, leaving a nominal .0005 inch to be removed in a subsequent operation as will appear.

Since the length and width of the liner blank may be increased by the rolling operation of step II, step III consists in finish-shearing the blank to accurate dimensions preparatory to forming it into cylindrical shape. It will be convenient to take a specific size of liner in this discussion, and it, therefore, will be assumed that it is desired .to fabricate a liner i5 having a .060 inch wall and providing a four-inch standard cylinder bore. This size, which happens to be one that is,standard for many truck engines, includes a four-inch internal diameter and a seven and three-quarter inch length. The length to which the blank is finish-sheared is determined from the diameter of the liner to be formed and from the thickness vof the blank after the operation of step II. In-

asmuch as the blank will be formed to cylindrical shape before the removal of: the final .0005

inch of wall thickness, it is preferred to form the liner so as initially to have an inside diameter of 3.999 inches. Thus, considering the radius of a neutral surface of a cylindrical sleeve to be greater than the inside radius of the sleeve by dimensions based upon the desired finished size of the liner, the increase in the dimensions of the blank by the rolling operation of step II provides ample metal for finish-shearing to the length mentioned.

The fourth step of the process, shown at IV in Fig. 3, involves forming a plurality of indentations 20 in one surface of the finish-sheared blank. These indentations 20 may have across section which is approximately conical, as shown in Fig. 10, or they may have any other appropriate cross-section such as parabolic, pyramidal, or the like, and may have rough interior surfaces. Although the dimensions of these indentations 20 are not critical, a surface interruption of approximately .015 and a depth of approximately .005 inch is preferred. The spacing between indentations, also not critical, may be three-eighths inch, for example, An indented sheet 2| shown in Fig. 9, illustrates one arrangement of indentations, other arrangements, however, being equally appropriate. The indentations 20 may be formed by any appropriate means as, for example, by impressing them in the flat sheet with a roller having appropriately shaped points formed on the rolling surface thereof.

The fifth step in the process is that shown at V in Fig. 3, and consists of preforming the ends of the finish-sheared and indented blank into a curvature which, in the present illustration, has a theoretical inside radius of 1.9995 inches. Details of this are indicated diagrammatically in Fig. 4, and the blank having both ends thus curved is shown in Fig. 5. Although the method shown for performing this operation is preferred, it Will be understood that under certain circumstances other means may be employed to put this initial curvature on the ends of the blank. In the illustration of Fig. 4, a lower die 25 is shown as being cooperable with an upper die 26 to impart a desired curvature 27 to the indented and finish-sheared blank 2!. Since, in the illustration given, the liner is to have an initial 3.999 inch inside diameter and .0605 inch wall thickness, it may be seen that the curvature of the upper die surface 25 will have a predetermined radius of somewhat less than 1.9995 inches, whereas the lower die surface 25 will have a radius substantially .0605 inch greater. Thus, when the dies are pressed upon the ends of the blank 2 l they will put an initial curvature therein as illustrated at 27 and 28 in Fig. 5, which is that proper to provide the ultimate desired radius in these areas of the finished liner. It is understood, of course, that the blank 24 is formed in a direction to dispose the indentations 20 at the inner or concave surface thereof.

The sixth step, indicated at VI in Fig. 3, is the formation of the blank 2! to approximately cylindrical shape throughout its length. This may be done by pyramid rolls or the like such as those diagrammatically illustrated at 30 in Fig. 6. The blank 2|, with its ends preformed as described for step V, is passed between these rolls and is caused by them to assume an approximately cylindrical shape of the proper diameter.

It is very likely that, at this stage, careful inspection of the portions of the blank 2! adjacent the free edges of the preformed ends will show them not to be formed accurately to the desired radius of the finished liner, it being extremely diificult to maintain the desired curvature to the very edge of a strip thus formed. Step VII, therefore, comprises a conforming operation which is illustrated in Fig. 7. The generally cylin- :drical blank'zi dram-step VI isin'serted into a special jig or former assembly 3| comprising a cylindrical body 32 having an accurately formed cylindrical inner surface of a diameter at least equal to the predetermined outside diameter of the desired liner i5, which in the present example would be 4.120 inches, thus to prevent overlap of the contiguous free ends of the liner blank 2|. Interiorly of both the body 32 and the-inserted liner blank 2 I, a cage 33 cooperates with a tapered .m'andrel 34 to retain a plurality of tapered rollers 35 in angular spaced relation adjacent the inner surface of the liner blank 2|. As is clear from Fig. '7, the complementary tapered rollers 35 and mandrel 34 comprise an expandible assembly for conforming the liner blank 2| to an accurate cylindrical shape, expansion of the assembly being effected by axial movement of the mandrel 34 as the rollers are caused to revolve therearound. Such a former assembly is described in detail in the above mentioned Patent No. 2,361,434. It will be noted that, while the purpose of step VII is primarily to conform the blank 2| to an accurate cylindrical shape, the rolling operation serves also to reduce any craters or like deformations produced at the inner surface of the blank 2| by the indenting operation of step IV.

Upon the completion of the conforming operation of step VII, the liner blank 2| undergoes the operation of step VIII in which it is trimmed accurately to a desired vertical length. This operation is preferably performed in a lathe, and the blank may be mounted and clamped on an appropriate mandrel. The upper and lower ends of the blank 2| are trimmed square to the cylindrical axis and the chamfer l9 at the lower end is formed.

The cylindrical blank 2| may now undergo step IX in which the upper end is flared as shown at It in Figs. 1 and 2. This may be done by placmentioned .0005 inch of wall thickness originally provided for finishing is removed. It is desirable that approximately .0002 inch on the diameter be left after this operation for removal in step XV to be described. The smooth cylindrical finish provided as a result of the honing operation of step X, of course, removes any remaining inwardly projecting deformations resulting from the indenting operation of step IV and not fully reduced by the rolling operation of step VII.

The next step of the process is that indicated at XI in Fig. 3 and consists of the surface hardening. Usually only the inside surface of the cylinder is hardened, although this is not a restriction, and it is preferred that this be a nitriding or cyaniding process or its equivalent chemical case-hardening operation. Operations of this kind are explained in some detail in applicants above-mentioned Patent No. 2,361,434. Preferably, the flared portion of the liner is retained in its original relatively soft state, as by the application of Sel-Nite, or the like. The nitriding operation is carefully controlled so as to obtain the proper hardening of the desired surface and to limit the amount of change in size, if any, of the liner.

The next step in the process, shown as XII in Fig. 3, comprises grinding the contiguous edges of the cylindrical blank 2| which abut to form the seam II. In performing this operation, the cylindrical liner 2| is disposed ove'ran appropriate mandrel or adapter 38, as shown in Fig. 7, so as to enforce a slight separation of these edges. Preferably, a mandrel operable as a magnetic chuck is used, such a mandrel being clearly describedin applicants copending application Serial No. 143,697, filed February 11, 1950. Where it is assumed that the initial bore of the liner should be 3.999 inches, the mandrel 38 may be 4.090 inches in diameter, thereby spreading the gap only a slight amount, as the minimum gap provides maximum magnetic efficiency. The upper part of the adapter 38 is provided with agroove 39 over which the gap between the edges of the cylindrical blank 2| is, disposed. It will be noted that the size of the gap, as shown in Fig. 8, is greatly exaggerated, as isalso an abrasive cutting wheel 40 shown adjacent thereto.

The cutting wheel 40, freely receivable in the groove 39, is employed to grind the gap to a predetermined width having a very close tolerance, and is beveled slightly so as to cause the ground edges thus formed to'go together in substantially surface engagement when the gap is closed to form the seam It will be noted that the final sizing operation of step XII is performed after the hardening operation of step XI so that not only may any growth of the blank 2| during the latter step be eliminated, but, as will normally be the case, the slight growth due to the hardening operation will provide the increased circumference to permit reduction of these edges to a smooth ground finish. Further, the desired internal diameter may be controlled very accurately by proper determination of an appropriate width of gap produced by the grinding opera:- tion of step XII. In other words, to provide a 4.000 inch bore, and assuming the cylindrical blank 2| to be mounted upon a 4.090 inch mandrel 39, a gap width of approximately .283 inch is indicated.

The completely formed blank 2| may now undergo the finishing steps of the process which include step XIII, an exterior plating operation and step XIV, an interior finishing operation.

The plating operation of step XIII consists of "applying copper, preferably electrolytically, to the outside of the liner for the purpose both of improving the efficiency of heat transfer between the liner i5 and the cylinder block l8 and for securing an adequate press fit in the block l8 without distortion of the liner. The inner surface is lacquered prior to the actual plating operation to prevent the depositing of copper thereon. If desired, the plating operation may be performed with the seam of the liner l5 opened so as to provide soft copper edges in the seam H. A .0001 inch deposit of copper on these edges will fill irregularities left from the grinding operation and provide a very accurate joint in the seam [1. Any copper extruded into the liner |5 upon closure of the seam II should be removed.

The final step is that shown as XIV in Fig. 3 and includes removal of the lacquer, above-mentioned, from the inside of the liner and a final honing of the interior surface. This final honing operation provides a very smooth wearing surface which contributes greatly to the life of the liner. Normally, the removal of .0002 inch on the diameter is sufficient, although more or less metal may be removed in this operation if necessary to bring the liner to the desired finished diameter of 4.000 inches.

It has been found that cylinder liners fabricated in the foregoing manner may, in spite of their thin wall structure, be made commercially with an ovalization limit not exceeding .002 inch and, in addition, may be very accurately sized. Further, the incorporation of indentations in the wearing surface permits the application of a very smooth finish to the wearing surface without the heretofore consequent problem of non-retention of oil on the walls of the cylinder, particularly during idleness of the engine. Moreover, the retention of oil at all engine operating speeds materially reduces heat and wear from friction. Efficient lubrication of cylinder walls, particularly at low engine speeds, has long been a problem in the automotive field. These qualities, among others inherent from the process, provide a cylinder liner which has distinct superiorities over previously known liners.

Clearly, there has been described an oil retaining cylinder sleeve and a method of making it which fulfill the objects and advantages sought therefor.

It is to be understood that the foregoing description and the accompanying drawings have been given only by way of illustration and example. It also is to be understood that changes in form of the sleeve, rearrangement of substitution of equivalent steps in the process, and the elimination of certain steps in the process, which will be obvious to those skilled in the art, are contemplated as within the scope of the present invention, which is limited only by the claims which follow.

What is claimed is:

1. A method of fabricating a sleeve-like cylinder of metal, comprising the steps of providing a generally fiat blank of metal, reducing said blank to a uniform predetermined thickness, indenting at least one surface of the blank to form a plurality of cavities therein, cutting the blank to a length predetermined in accordance with a desired diameter of the finished cylinder, curving the blank to a substantially uniform radius with the indented surface on the inside of the curved blank, and inserting the curved blank into a cylindrical jig and conforming it therein to a precise cylindrical shape while at the same time reducing any craters or like deformations produced at the inner surface of the blank in the aforementioned step of indenting.

2. The method of claim 1 wherein the step of simultaneously conforming the curved blank and reducing the craters or like deformations comprises inserting an expandable roller assembly interiorly of the curved blank and rolling the blank so as to conform the same accurately with the cylindrical jig while reducing the craters or like deformations.

3. The method of claim 2 further characterized by honing the interior surface of the sleeve after it is formed, hardening the honed surface, and rehoning the hardened surface.

4. The method of claim 3 further characterized by grinding the juxtaposed edges of the conformed blank after the hardening of the interior surface thereof to remove any increase in the curved length of the blank due to hardening and to shape said edges for subsequent precise abutment thereof, and plating the ground edges with a soft metal for subsequent sealing abutment thereof.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,233,438 Barengueras July 17, 1917 1,787,255 Klocke Dec. 30, 1930 1,794,184 Leis Feb. 24, 1931 1,882,956 Sandler Oct. 18, 1932 1,913,204 Larzelere June 6, 1933 1,922,304 Klocke Aug. 15, 1933 1,944,380 Vance Jan. 23, 1934 1,971,433 Tartrais Aug. 28, 1934 2,086,841 Bagley et a1. July 13, 1937 2,248,530 Granger et a1. July 8, 1941 2,279,671 Ford Apr. 14, 1942 2,314,604 Van der Horst Mar. 23, 1943 2,324,547 Wagner July 20, 1943 2,361,434 Surtees Oct. 31, 1944 2,368,007 Delahan Jan. 23, 1945 2,414,931 Colwell Jan. 28, 1947 2,600,800 1952 Pace June 17,

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