US2777740A

US2777740A - Piston-ring construction

Info

Publication number: US2777740A
Application number: US405565A
Authority: US
Inventors: Pien Hsia-Si
Original assignee: Wilkening Manufacturing Co
Current assignee: Wilkening Manufacturing Co
Priority date: 1954-01-22
Filing date: 1954-01-22
Publication date: 1957-01-15
Anticipated expiration: 1974-01-15

Description

Jan. 15, 1957 HSlA-Sl PlEN 2,777,740

PISTON-RING CONSTRUCTION Filed Jan. 22, 1954 4 Sheets-Sheet 2 INVENTOR. HSlA-Sl 'PIEN BY KW i ATTORNEY Jan. 15, 1957 HSlA-Sl PIEN 2,777,740

PISTON-RING CONSTRUCTION Filed Jan. 22, 1954 4 Sheets-Sheet 3 u INVENTOR. HSlA-SI PIEN ATTORNEY Jan. 15, 1957 HSlA-SI PIEN 2,777,740

PISTON-RING CONSTRUCTION Filed Jan. 22, 1954 4 Sheets-Sheet 4 INVENTOR.

HSlA-SI PIEN 5 E. ,2 m' NE) United States Presto PISTON-RING CONSTRUCTION Hsia-si Pien, Drex el fill, Pa., assignor to Wiikening Manufacturing Co., Philadelphia, Pa., a corporation of Delaware Application January 22, 1954, Serial No. 405,565

Claims. (Cl. 30924) The present invention relates to certain new and useful 3-piece piston-rings for internal combustion engines and the like and to a novel spacer-and-expander for such type piston-rings. v

There has been a long-felt need for non-bottoming, self-expanding piston-rings, namely piston-rings which exert an expansive force irrespective of whether or not the piston-ring is in contact withthe bottom of the ringreceiving groove, and which effect a uniform circumferential engagement of the piston-ring sealers or rails against the cylinder walls.

Recently a number of such non-bottoming circumferentially expansible piston-rings have been developed which have achieved a more or less satisfactory level of performance. However by and large such self-expanding piston-rings have been of relatively complex construction and have required a large amount of bending and milling in their fabrication. Moreover, due to their structural complexity such heretofore developed piston-rings have in some instances developed poor performance characteristics after a period of use, with the spacer-and-expander portion of the piston-ring becoming deformed and causing malfunction.

This invention has as an object the provision of a nonbottoming circumferentially expansible piston-ring which does not require any support and is capable of functioning for greatly protracted periods in a highly satisfactory manner.

Another object of the present invention is a piston-ring which will conform to the cylinder-wall notwithstanding any slight out-of-roundness or out-of-cylindrical shape of the cylinder-wall due either to distortion of the cylinderwall or due to wear, and one which will break in readily.

Another object of the present invention is a piston-ring which will bear against the cylinder-wall with uniform or equalized outward radial pressure and which will efiectively seal against the cylinder-wall and which may have a relatively high unit of contact-pressure per unit of contact-area with the cylinder-wall, and which will provide adequate lubrication with good oil control.

For the purpose of illustrating the invention, there are shown in the accompanying drawings forms thereof which are at present preferred, although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized and that the invention is not limited to the precise arrangement and organizations of the instrumentalities as herein shown and described.

In the accompanying drawings in which like reference characters indicate like parts:

Figure 1 is an exploded perspective view of a threepiece piston-ring of one embodiment of the present invention.

Figure 2 represents a side sectional view of the threepiece piston-ring shown in Figure l in position in the ringreceiving groove of a piston with the sealing-rings of the piston-ring contacting the cylinder-wall. i

Figure 3 is a plan view of a fragmentary portion of a cut strip of band or ribbon of flat spring metal, such as spring-steel, from which the spacer-and-expander ofthe three-piece piston-ring of Figure 1 is formed, showing the first stage in the formation of the spacer-and-expander.

Figure 4 is an exploded perspective view of another embodiment of the three-piece piston-ring of the present invention. v

Figure 5 represents a side sectional view of the threepiece piston-ring shown in Figure 4 in position in the ringreceiving groove of a piston with the sealing-rings of the pistonring contacting the cylinder wall.

I Figure 6 is a plan view of a fragmentary portion of a cut strip of band or ribbon of flat spring-metal, such as spring-steel, from which the spacer-and-expander of the three-piece piston-ring of Figure 4 is formed, showing the first stage in the formation of the spacer-and-expander.

Figure 7 is an exploded perspective view of another embodiment of the three-piece piston-ring of the present invention.

Figure 8 represents a side sectional view of the threepiece piston-ring shown in Figure 7 in position in the ring-receiving groove of a piston with the sealing-rings of the piston-ring contacting the cylinder-wall.

Figure 9 is a plan view of a fragmentary portion of a cut strip of band or ribbon of flat spring metal, such as spring-steel, from which the spacer-and-expander of the three-piece piston-ring of Figure 7 is formed, showing the first stage in the formation of the spacer-and-expander.

Figure 10 is an exploded perspective view of another embodiment of the three-piece piston-ring of the present invention.

Figure 11 represents a side sectional View of the threepiece piston-ring shown in Figure 10 in position in the ring-receiving groove of a piston with the sealing-rings of the piston-ring contacting the cylinder-wall.

Figure 12 is a plan view of a fragmentary portion of a cut strip of band or ribbon of flat spring metal, such as spring-steel, from which the spacer-and-expander of the three-piece piston-ring of Figure 10 is formed, showing the first stage in the formation of the spacer-and-expander.

Referring to Figures 1 and 2 for one embodiment of the piston-ring of the present invention, the piston-ring shown therein comprises an upper or top thin flat sealingring, oil scraper or oil control ring element 2%, a bottom or lower sealing-ring, oil scraper or oil control ring eleent 21, and a spacer-and-expander designated 22 comprising a continuous axially corrugated circumferentially expansible ring having its ends 19 abutting when the spacer-and-expander is operatively positioned. The operative position of the spacer-and-expander is shown in Figure l where ends 19 are abutting. i

The axially corrugated spacer-and-expander 22 has a generally zig-zag configuration and includes sealing-ringengaging axial surfaces 23 at its upper and lower peaks. designated 24. The sealing-ring-engaging amal surfaces 23 when in operative position (see Figure 2) contact the inner edge 25 of the sealing-

rings

20 and 21. Radially projecting tabs, fingers or projections 26 on the underside of peaks 14 comprise the supporting or seating surfaces of spacer-and-expander 22 and space sealing-

rings

20 and 21 respectively against top side wall 27 and bottomside. wall 23 of ring-receiving groove 29 of piston 30, as shown in Figure 2. v

Each of sealing-

rings

20 and 21, whichare referred to for the sake of brevity as a seal or .rail is preferably made of a flat band of steel although they may be formed from'other suitable hard drawn metal.

The sealing-

rings

20 and 21 can be made by coiling a metal. band into a 'coil of suitablev diameten'and'then cutting theindividualcouvolutions to form the sealsjor by coiling such a band and cutting off each convolution as it is-formed.

The outer cylinder-contacting or contact-edges 31 of sealing-

rings

20 and 21 can be plated with chromium to provide for longer life.

The sealing-

rings

20 and 21 are each split or provided with a gap 32, at one point, but are of such diameter that when the outer edge 31 of seals 21) and 21 contacts the cylinder-wall 37 as shown in Figure 2, the gap 32 is approximately closed. Sealing-ring gap 32 is formed when each seal is cut from the coil as indicated above.

The spacer-and-expander 22 is preferably made of spring-steel or other spring metal. Thus a flat band 33 (see Figure 3) is recessed by cutting away the side edges to form a series of recesses or grooves 34, and projections 26 alternately extending from either side but falling short of the full width of band 33. These projections 26 are the spacer elements 26 in the finished spa-cer-and-expander 22. The uncut portions of fiat band 33 comprise the pressure legs 18 and are of somewhat greater length than the projections 26.

After fiat band 33 has been milled or punched to the form shown in Figure 3, tabs 26 are bent outwards in the same direction along dotted line 36 (see Figure 3) and the band is convoluted to form the spacer-'and-expander 22. Alternatively, if fiat band 33 requires treatment, such as hardening, drawing and/ or tempering this can be accomplished prior to or after effecting the cutting 'and/ or bending.

The axially corrugated spacer-and-expander 22 is nonbottoming circumferentially compressible and when operatively positioned maintains sealing-

rings

20 and 21 against cylinder-wall 37 (see Figure 2) at a relatively high unit of contact pressure per unit of contact area.

Good oil control is effected by oil passageways 34 formed by the recesses, slits or slots, in spacer-and-expander 22 intermediate 'the pressure legs 18. Thus, oil scraped from the cylinder-wall 37 by sealing-

rings

20 and 21 during their reciprocal movement within the cylinder is removed through oil passageways 34 of the pistonrin-g into the innermost portion of rin -receiving groove 29 from where it is removed through drain hole 39 through the piston wall to the inner chamber of the piston and then to the crankcase.

The spacer tabs 26 may be positioned anywhere along the innerside of peaks 24 of spacer-and-expander 22 and may be of different widths. Thus, the width of spacer tabs 26 may be substantially co-extensive with the widths of the peak 24 between the pressure legs 18, or more preferably, spacer tabs 26 may be of somewhat lesser width, as is shown in the drawings. Spacer tabs 26 should be of such length so a to prevent wobbling of

rails

20 and 21 during the reciprocal movement of the piston.

The spacerand-expander 22 can be modified, as by altering the angles between pressure legs 18 and peaks 24, such as by varying the angle between the peak 24 and pressure legs 18. Alternatively, pressure legs 18 may be widened and perforated to provide oil passageways therethrough.

In the embodiment of my invention shown in Figures 4 through 6, the spacer-and-expander 40 is provided with a modified form of spacer elementsv 41 and '42. However, in other respects the spacer-and-expander 40 is similar to spacer-and-expander 22.

The spacer element 41 compn'ses a radially-extend- 4 vention achieves a high degree of spacing support for the rails.

The spacer-and-expander is formed from flat band 43, shown in Figure 6, by cutting the band along the lines shown, bending the

spacer elements

41 and 42 along the dotted lines and convoluting the band to produce the spacer-and-expander 40 heretofore described.

In the embodiment of my invention shown in Figures 7 through 9, the sp-acer-and-expander 45 comprises an xially corrugated slotted flat band having rail-engaging tabs 46 at its peaks 47. Rail-engaging tabs 46 extend axially beyond the outer surface '52 of peaks 47 of spacerand-expander 45. The rail-engaging tabs 46, when operatively positioned contact the inner edge 25 of sealingrings 21 and 21 (see Figure 8). The outer surface 52 of peaks 47 serves as a seating surface and spacer element for sealing-rings 2d and 21. When spacer-and-expander 45 is operatively positioned in ring-receiving groove 29 its free ends 48 are abutting (as shown in Figure 7).

The spaccr-and-expander 45 is preferably slotted such as by slots 53 within the body portion thereof to provide for more ready circumferential expan-sibility and compressibility.

The spacer-and-expander 45 is constructed from a flat slotted band (see Figure 9) bearing tongues or tabs 46 alternately positioned thereon at regularly spaced intervals. Such tabs or fingers are bent along dotted lines 50. The band is axially orrugated in a sine-curve fash ion, forming peaks 47. The sealing-ring-engaging tabs 46 are formed by bending the projections 46 along dotted line 50, and the band is convoluted to form the spacerand-expander 45. V

In the embodiment of my invention shown in Figures I 10 through 12, the spacer-and-expander 66 comprises ing tab 41 perpendicular to rin -engaging surface 23 of peak 24 and abutting a pressure leg 18. Spacer element 42 is an angularly directed tab abutting the other pressure leg 18 of the same peak 24. As seen in Figure 5, spacer element 41 supports'the rail engaged by its peak 24, whereas spacer 42 extends inwardly and furnishe support for the opposite raiL. This embodiment of my inan axially and radially corrugated fiat band having spacer tabs 68 and rail-engaging tabs 70, the latter being axial extensions of the radial innermost portion 6? of spacerand-expander 66. In the embodiment shown in the drawings, three spacer tabs 68 are provided for each railengaging tab 70. Spacer tabs 68 project axially outwardly from the body of spacer-and-expander 66 for a smaller distance than rail-engaging tabs 70. As seen in Figure 10, a spacer tab '68 is provided at the radial extremity of the radial corrugation with a spacer tab 68 intermediate said radially outwardly disposed spacer tab and the rail-engaging tab 70 with the outer axial surface 73 of each spacer tab 68 serving as a seating surface for

rails

20 and 21. i

The free ends 72 of spacer-and-expander 66 abut when spacer-and-expander 77 is operatively positioned (as shown in Fig. 10).

The axial corrugations adjacent the

tabs

68 and 70 provide oil passageways. If desired, spacer-and-expander 66 may be slotted by axial spaced slots to provide additional oil passageways.

The spacer-and-expander 66 is milled or punched from a flat band (see Figure 12) to yield rail-engaging tongues or tabs 70 positioned at regularly spaced intervals on both margins, with a plurality (in the embodiment shown, three) of spacer tabs 68 therebetween, and is then radially corrugated and convoluted to form a finished spacer-andexpander.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiments be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Having fully described my invention, 1 claim:

1. A composite 3-piece non-bottoming piston-ring adapted to be confined within the ring-receiving groove of a piston comprising a pair of parallel-spaced sealingrings adapted to be disposed closely adjacent the sidewalls of said ring-receiving groove, an axially corrugated spring-meta spacer-and-expander disposed between a pair of sealing-rings with its ends abutting each other, said spacer-and-expander comprising an axially corrugated relatively thin member having radially outwardly extending sealing-ring seating tabs extending from the innerside of its peaks for a distance substantially greater than the cross-sectional thickness of said peaks, the axially outermost surface of said outwardly-extending radial tabs comprising a supporting surface on which the sealing-rings are seated, the radially outer surface of the peaks of said axially corrugated member which is juxtaposed to said radial supporting surface overlapping and engaging the inner peripheral edges of the sealing-rings, said sealing-rings and spacer-and-expander being so constructed and arranged that when the sealing-rings are collapsed to sealing diameter and confined within the side-walls of said ring-receiving groove with the spacer-and-expander disposed between them and the aforesaid spacer-and-expander sealing-ring engaging outer surface engaged with the inner peripheral edges of said sealing-rings, the spacerand-expander will be compressed circumferentially and will urge the sealing-rings outwardly by means of the aforesaid ring-engaging surfaces.

2. A composite 3-piece non-bottoming piston-ring adapted to be confined within the ring-receiving groove of a piston comprising a pair of parallel-spaced sealingrings adapted to be disposed closely adjacent the sidewalls of said ring-receiving groove, an axially corrugated spring-metal spacer-and-expander disposed between said pair of sealing-rings with its ends abutting each other, said spacer-and-expander comprising an axially corrugated relatively thin member having radially outwardly extending sealing-ring seating tabs extending from the inner side of its peak for a distance substantially greater than the cross-sectional thickness of said peaks, the axially outermost surface of said outwardly-extending radial tabs comprising a. supporting surface on which the sealingrings are seated, the radially outer surface of the peaks of said axially corrugated member which is juxtaposed to said radial supporting surface overlapping and engaging the inner peripheral edges of the sealing-rings, oil passageways for removing oil through said piston-ring, said sealing-rings and spacer-and-expander being so constructed and arranged that when the sealing-rings are collapsed to sealing diameter and confined within the side-walls of said ring-receiving groove with the spacerand-expander disposed between them and the aforesaid spacer-and-expander sealing-ring engaging outer surface engaged with the inner peripheral edges of said sealingrings, the spacer-and-expander will be compressed circumferentially and will urge the sealing-rings outwardly by means of the aforesaid ring-engaging surfaces.

3. A composite 3-piece non-bottoming piston-ring adapted to be confined within the ring-receiving groove of a piston comprising a pair of parallel-spaced sealingrings adapted to be disposed closely adjacent the sidewalls of said ring-receiving groove, an axially corrugated spring-metal spacer-and-expander disposed between said pair of sealing-rings with its ends abutting each other, said spacer-and-expander comprising an axially corrugated relatively thin member having a pair of radially outwardly extending sealing-ring seating tabs extending from the inner side of its individual peaks, one of said pair of radially extending tabs being perpendicular to the plane of its peak and comprising a seating surface for the sealing-ring engaged by its peak, the other tab of said pair of radially extending tabs being angularly directed inwardly and operatively engaging the opposite sealing-ring, the radially outer surface of the peaks of said radially corrugated member which is juxtaposed to said radial supporting surface overlapping and engaging the inner peripheral edges of the sealing-ringsysaid sealing-rings and spacer-and-expander being so constructed and arranged that when the sealing-rings are collapsed to sealing diameter and confined within the side-walls of said ring-receiving groove with the spacer-and-expander disposed between them and the aforesaid spacer-and-expander sealing-ring engaging outer surface engaged with the inner peripheral edges of said sealing-rings, the spacerand-expander will be compressed circumferentially and will urge the sealing-rings outwardly by means of the aforesaid ring-engaging surfaces.

.4. A spacer and-expander for multi-seal-piston-rings adapted to intervene a pair of sealing-rings and to maintain said pair of sealing-rings disposed within the ringreceiving groove of a piston and urged outwardly comprising an axially corrugated spring-metal circumferentially compressible relatively thin spacer-and-expander having radially-outwardly extending sealing-ring seating tabs extending from the inner side of its peaks for a distance substantially greater than the cross-sectional thickness of said peaks, the axially outermost surface of said outwardly extending radial tabs comprising a supporting surface for seating the sealing-rings, the radially outer surface of the peaks of said axially corrugated member which is juxtaposed to said radial supporting surface constructed and arranged to overlap and engage the inner peripheral edges of the sealing-rings so that when said spacer-and-expander is operatively engaged with said sealing-rings and collapsed to cylinder diameter and confined within the side-walls of the'ring-receiving groove with the sealing-ring-engaging outer surface engaged with the peripheral edges of the sealing-rings, the spacer-andexpander will be compressed circumferentially and will urge the sealing-rings outwardly by means of the aforesaid ring-engaging surfaces.

5. A spacer-and-expander for multi-seal-piston-rings adapted to intervene a pair of sealing-rings and to maintain said pair of sealing-rings disposed within the ring receiving groove of a piston and urged outwardly comprising an axially corrugated spring-metal circumferentially compressible relatively thin spacer-and-expander having a pair of radially-outwardly extending sealing-ring seating tabs extending from the inner side of its individual peaks, one of said pair of radially extending tabs being perpendicular to the plane of its peak and comprising a seating surface for the sealing-ring engaged by its peak, the other tab of said pair of radially extending tabs being angularly directed outwardly and adapted to operatively engage the opposite sealing-ring, the radially outer surface of the peaks of said axially corrugated member which is juxtaposed to said radial supporting surface constructed and arranged to overlap and engage the inner peripheral edges of the sealing-rings so that when said spacer-and-expander is operatively engaged with said sealing-rings and collapsed to cylinder diameter and confined Within the side-walls of the ring-receiving groove with the sealing-ring-engaging outer surface engaged withthe peripheral edges of the sealing-rings, the spacer-and-expander will be compressed circumferentially and will urge the sealing-rings outwardly by means of the aforesaid ring-engaging surfaces.

References Cited in the file of this patent UNITED STATES PATENTS 2,220,948 Paton l Nov. 12, 1940 2,635,022 Shirk Apr. 14, 1953 2,637,607 Olson May 5, 1953 FOREIGN PATENTS 555,348 Great Britain Aug. 18, 1943