US2877072A

US2877072A - Piston-ring construction

Info

Publication number: US2877072A
Application number: US610051A
Authority: US
Inventors: Pien Hsia-Si
Original assignee: Wilkening Manufacturing Co
Current assignee: Wilkening Manufacturing Co
Priority date: 1954-01-22
Filing date: 1956-09-13
Publication date: 1959-03-10
Anticipated expiration: 1976-03-10

Description

March 10, 1959 HSlA-Sl PlEN 2,877,072

PISTON-RING CONSTRUCTION Filed Sept. 13, 1956 INVENTOR.

HSlA-Sl PI N PISTON-RING CONSTRUCTION l-lsia-Si Pien, Waltham, Mass., assignor to Willrening llglalnufacturing Co., Philadelphia, Pa., a corporation of e aware Original application January 22, 1954, Serial No. 405,565,

2 Claims. (Cl. 309-44) 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.

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 contactwitl'r the 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 pistonrings 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 expausible 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 eifectively 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 one form thereof, although it is to be understood that the various instrumentalities of which the invention consists can be various- 1y arranged and organized and that the invention is not limited to the precise arrangements 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 composite 3-piece piston-ring representing one embodiment of the present invention.

Figure 2 represents a side sectional view of the same, in position in the ring-receiving groove of a piston, with the sealing-rings of the piston-ring contactng the cylinderwall.

Figure 3 is a plan view of a fragmentary portion of a cut strip of band or ribbon of flat spring metal, such as Un rc d t s P ti tf 2,877,072 Patented Mar. .10, 9

ICE

spring-steel, from which the spacer-and-expander of the three-piece piston-ring of the present invention is formed, showing the first stage in the formation of the spacer-and expander. 7

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 fiat sealing-ring, oil-scraper or oil-control ring element 20, a bottom or lower sealing-ring, oil-scraper or oil-control ring element 21, and a spacer-and-expander designated 66, comprising a continuous radially corrugated circumferentially cornpre'ssible'and expansible ring'having its ends 72 abutting each other when the spacer-and-expander is operatively positioned. The operative position of the spacer-and expanderis shown in Figure 1 where ends 77 are abutting.

The spacer-and-expander 66 comprises an axially and radially corrugated fiat band of spring metal having spacer tabs 68 and rail-engaging tabs 70, the latter being axial extensions of the radial innermost portions 69 of spacer-and-expander 66. In the embodiment shown in the drawings, three spacer tabs 68 are provided intermediate each two rail-engaging tabs 70. Spacer tabs 68 project axially outwardly from the body of spacer-and-ex pander 66 for a smaller distance than rail-engaging tabs 70. As seen in Figure l, a spacer tab 68 is provided at the radially outward extremity of each of the radial corrugation, with a spacer tab'68 intermediate said radiallyoutwardly disposed spacer tab andthe rail-engaging tab 70; with the outer axial surface or end 73 of each spacer tab 68 serving as a seating surface for

rails

20 and 21.

The free ends 72 of spacer-and-expander 66 abut when spacer-and-expander 66 is operatively positioned (as shown in Figure 1).

The spaces between adjacent the

tabs

68 and 70 pro vide oil passageways. If desired, the spacer-and-expander 66 may be slotted or perforated by axially spaced slots or holes to provide additional oil passageways.

The spacer-and-expander 66 is milled or punched from a flat band (see Figure 3) to form the 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 embodiment 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 described the invention, the following is claimed:

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, a non-bottoming radially-corrugated circumferentially-expanding springmetal spacer-and-expander disposed between said pair of sealing-rings with its ends abutting each other and with such abutment causing the spacer-and-expander to resist circumferential compression when compressed by the sealing rings when mounted in the cylinder, said spacerand-expander comprising a radially corrugated band, a plurality of radially-outwardly disposed sealing-ring seat ing tabs on and extending axially from each of the two opposite edges of each of said corrugations, with the axially outermost surface of said seating tabs comprising supporting surfaces on which the sealing-rings are seated and constituting the sole axial spacing means between said asrao a sealing rings, said plurality of seating tabs providing axial support for said sealing-ring both along a zone near the outermost periphery thereof as well as along a zone spaced substantially inwardly from said first-mentioned zone, radially-thrusting ring-engaging tabs on the radially innermost portion of said 'spacer-and-expander having greater axial length than said seating tabs, the radially-outward surface of said radailly thrusting ring-engaging tabs 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 sealin rings are collapsed to cylinder diameter and confined within the side-walls of said ring-receiving groove with the spacer-and-expander disposed between them and the aforesaid radially thrusting rin -engaging tabs engaged with the inner peripheral edges of said sealing-rings, the spacer-and-expa'nder will be compressed circumferentially and will urge the sealing-rings outwardly by means of the aforesaid ring-engaging surfaces of said radially-thrusting ring-engaging tabs.

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, a non-bottoming radially-corrugated circumferentially-expanding springmetal spacer-and-expander disposed between said pair of sealing-rings with its ends abutting each other and with such abutment causing the spacer-and-expander to resist circumferential compression when compressed by the sealing rings when mounted in the cylinder, said spacerand-expander comprising a radially corrugated band having radially-outwardly disposed sealing-ring-seating and supporting tabs on which the sealing-rings are seated axially and constituting the sole axial spacing means between said sealing rings, and providing axial seating and support for said sealing-rings. both in a zone near the outermost periphery thereof as well as in a zone near the inner periphery thereof, radially-thrusting ling-engaging tabs on the radially innermost portion of said spacer-andexpander having greater axial length than said seating tabs, the radially-outward surface of said radially-thrusting ring-engaging tabs overlapping and engaging the inner peripheral edges of the sealing-rings, oil-passageways for removing oil through said piston-ring, said sealingn iugs and spaCenand-expander being so constructed arid; arranged that when the sealing-rings are collapsed to cylinder diameter and confined; Within. the side-walls of said ring-receiving groove with the spacer-and-expander disposed between them and the aforesaid radiallyathrusting snga tabs. sns 's wit h n 'p r tzhsra edges of said sealing-rings, the spacer-and-expander will be compressed circumferentially and will urge thesealingrings outwardly by means of the aforesaid surfaces of said rings, outwardly by means of the aforesaid ring-engaging surfaces of saidradially-thrusting ring-engaging tabs.

References Cited in the file of this patent UNITED STA'IfES PATENTS 2,229,578 Malpas Ian. 21 1241 2,297,104 Johnson Sept. 29, 1 942 2,302,959 Johnson Nov. 24, 1 942 2,656,230 Phillips Oct. 20, 1953 2,744,803 Marien May 8, 195,6