US1911736A

US1911736A - Piston ring

Info

Publication number: US1911736A
Authority: US
Publication date: 1933-05-30
Anticipated expiration: 1950-05-30

Description

y 30, 1933- F w. WXLKENlNG 1,911,736

PISTON RING Filed Feb. 16, 1951 16$ 57/ 1 J ll l l W 18 1 32 1 %A j m mm INVENTOR.

1% EedericK h/ilKeniy Patented May 30, 193 3 UNITED STATES PATENT OFFICE FREDERICK W. WILKENING, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO WILKENING MANUFACTURING COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A.

CORPORATION OF DELAWARE PISTON RING Application filed February 16, 1931. Serial no. 516,130.

The present invention relates generally to a class of piston rings commonly referred to as oil-control rings, and it relates more par: ticularly to a novel oil-controlring construction, whereby certain deficiencies and undesirable characteristics of the prior oil-control rings may be entirely eliminated, and whereby a much improved product may be obtained.-

Amohg the several practices followed heretofore in making oil-control rings, various types of openings have been employed to V convey the oil through the ring to the space between the ring and the back of the ring groove, and thence through holes drilled 1n the piston to the crankcase. Also various means have been employed to secure an effective contact between the outer periphery of the ring and the cylinder wall. No ade quate provision has been made to prevent the passage of oilfrom the space in back of the ring, to the cylinder wall above the ring through the clearance between the side or face of the ring and the side-wall ring groove.

Thus, even with adequate drainage through the ring and effective contact with the cylinder wall, it has not been possible to prevent efieetively the passage of oil around the ring and thence to the head of the piston.

To eliminate these deficiencies and overcome these undesirable characteristics inherent in the prior oil-control ring constructions, my'present invention contemplates a certain radially perforated and externally. double channeled ring whereby a substantially uniform outward radial pressure may be obtained, producing a complete uniformity of contact between the entire outer periphery of the ring and the cylinder under all conditions, and whereby the desired oil drainage through the radial perforations of the ring may bemaintained, and whereby also an effective contact may be obtained between the side face of the ring and the side-wall of the the piston into the combustion chamber at the same time permitting a proper and suflicient lubrication of the cylinder walland minimizing the frictional resistance and wear due to the 'rings- With the foregoing and other objects in v1ew, my invention consists of and includes certain features of construction which will appear more fully from the following detailed description.

For the purpose of illustrating my inven tion I have shown in. the accompanying drawing one form thereof which is'at present pre-- ferred by me, since the same has been found in practice to give "satisfactory and reliable results, although it is to be understood that.

the various instrumentalities of which my invention consists can be variously arranged and organized and that my invention is not limited to the precise arrangement and organization of the instrumentalities as herein shown and described.

Referring to the drawing in which like ref- I erence characters indicate like parts Figure 1 represents a fragmentary sectional view of a piston containing a piston ring of the present invention, in relation to the cylinder walls, shown on a much'enlarged scale.

Figure 2 represents a top plan view of the same shown in relation to the piston.

' Figure 3 represents a perspective view of an expander spring adapted to'form part of my novel ring construction.

The ring 11 of the novel construction of the instant invention is of the split cast iron type, to be mounted in the conventional ring groove 21 in which a series of radial oil drain holes or apertures 24 are provided, intermediatethe bottom' of the ring groove 21 and the interior of'the piston. Outward radial tension is preferably built into the ring, so

that the ring becomes self-expanding.

A double channel 12 is provided in the outer face of the ring 11, preferably spaced equidistantly from the two plane parallel faces 15 and 16' thereof, so as to provide a pair of outer .

annular bearing surfaces

17 and 18 respectively, onthe outer periphery of the ring,;o f approximately equal width. The

double channel 12 is composed of an outer substantially rectangular portion '13 and an inner portion 14-preferably of semicircular.

or other curved cross-section; the diameter or maximum width of said nner channel portion 14 being less than the width of thereotangular channel portion 13 of the said double channel 12; thereby providing an outer rectangular channel and an inner curved channel. 1 e

The axial width of theouter rectangular channel 13 is so proportioned with respect to the width of the ring, thatit will occupy approximately two-thirds, more or less, of the width of the ring, thereby providing annular bearing surfaces 17 and '18, each approximately one-sixth, more or less, of the Width of'the ring.

A series of apertures 19, preferably in. the formof generally radial circular openings, are provided through the ring'from the inner circular channel 14 to the inner diameter 20 ofthe ring.- The radial apertures 19 may be of any suitable number and are preferably equidistantly spaced with respect to each other, and are preferably of a diameter substantially equal to, or slightly greater than, the maximum axial width of the inner channel' 14 andslightly less than the axial width of theouter channel 13.

The radial width of the upper plane sideface 15, of the ring 11, which contacts with the corresponding side wall of the ring groove, is reduced to approximately onefourth the total radial width ofthe ring by any suitable means, preferably by providing a slight bevel 30 at an angle of approximately five degrees, more or less, with the lane of the ring. This, while not apprecia ly'nor materially decreasing the width of the upper annular bearing or cylinder. contact surface 17, does materially reduce the upper efi'ective contact face or side of the ring which is juxtaposed to the corresponding side wall of the ring groove 21. I

Toaugment or replace the outer radial pressure inherent in the body of the ring, aflat steel spring ribbon expander 25 is provided, being suitably corrugated in a radial direction to provide alternate inner and

outer contact points

26 and 27, respectively, for engagement with the bottom of thering groove and the inner diameter of the ring respectively ;preferably having its inner contact points 26 suitably weakened or narrowed as indicated particularly in Figures 1 and 3. The radial expander spring 25 is interposed between the bottom of the ring oove 21 and the inner diameter of the ring. One of the advantages of my present novel ring construction is inproviding the necessary drainage through the ring in the form of a comparativelylarge number of comparatively small circular apertures, equidistantly spaced, which weaken the cross-section of the ring to a minimum extent for a given aggregate cross sectional area of apertures, and which, by dividing the circumference of the ring into comparatively very short alternate perforated and non-perforated sections, -per mits the tension inherent in the ring to be distributed substantially uniformly through the circumference of the ring.

By reason also of the inner channel 14, an increased effectiveness in the drainage of oil through the ring is obtained, because said inner channel 14 tends effectively to guide the oil film to the radial apertures 19.

Because the area of the upper side contact surface 15 of the ring has been considerably reduced, by the slight beveling 30, the pressure per unit of area exerted between the upper side face 15 and the corresponding side wall of the ring groove, on the down stroke of the piston, is considerably increased. The effect of this increased unit pressure is to enable the comparatively narrow contact surface 15 to effectively cut through the fihn of oil between the ring and the side of the ring groove and approach a perfect metal to metal contact between the side face of the ring and the side wall of the ring groove, thus effectively preventing the passage of oil from the space in back of the ring to the cylinder wall above-the ring and thence to the head of the piston.

In certain instances the axial width of the ring is preferably made from three to seventhousandths of an inch less than the width of the roove into which said ring is intended to be pdaced, thereby creating a clearance space 31 between the side wall of the ring and the lower side walls of the ring groove.

The action of the. ring is as follows:

Because the area of the outer peripheral cylindrical contact face of the ring has been considerably reduced by the double channel 12, the comparatively narrow

annular contact surfaces

17 and 18 of the ring are urged into contact with the cylinder wall with a greater pressure per unit of contact area, and tend to break through the oil film adhering to the cylinder surface, and to ride back and forth over a comparatively thinner oil film, than what would obtain were the contact surface of the ring equal to the entire width of the ring. This causes some of the oil film to be scraped onto the'side walls of the outer channel 13 during the successive strokes of the piston. The oilfilm thus gathered on the walls of the outer channel 13 then passes onto the curved walls of the inner channel 14, from whence it is effectively drained through the radial apertures 19. The oil is thus gathered behind the ring and is then drained back into the crankcase through the drain apertures 24 extending through the piston wall. On the downward stroke of the piston the ring will be forced upwardly in the groove by the frictional drag of the cylinder wall upon the ring, and because of the much increased pressure per unit area between the upper contact face 15 of the ring and the corresponding side wall of the ring groove, the film of oil adhering to the side surface of the ring and the side wall of the ring groove is efiectively cut, effectively preventing the passage of any oil or compressed gases between these surfaces.

For fitting cylinders which may be worn and somewhat out of round, and in general for use as replacement. rings, 'my novel piston ring may be made without any or with lessened outward radial tensionin the body of the ring, that is, with the ring normally in a generally collapsed condition, and the radial width of the ring may be decreased sufficiently to provide a somewhat pliable ring body which may then be expanded outwardly by the radial expander spring 25 as shown particularly in the drawing. In this form of my novel ring construction, the ring may be caused to follow any slight irre larities in the cylinder wall, by reason of lts somewhat pliant and lifeless condition and by reason of the uniformly distributed outward radial pressure exerted upon the ring by the expander spring 25 bearing against it 'at a series of uniformly spaced points.

In this form of my present invention, the comparatively narrow bearing

surfaces

17 and 18 may be urged into contact with the cylinder wall with substantially uniform pressure of suflicient degree to cause an eflec-' tive gathering of the oil into the channel 13 and a drainage of the oil from the walls ofsaid channel and from the walls of the inner channel 14 through the small radial openings 19, the high unit pressure between the upper side surface 15 and the corresponding side wall of the groove effectively preventing the passage of oil between thesesurfaces.

I am aware that my invention maybe embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore-desire the present embodiments to be considered in all respects as illustrative and not restrictive, reference being hadto the appended claims rather than to the foregoing description to indicate the scope of the invention.

Having thus described 111 invention, what I hereby claim as new and esire to secure by Letters Patent, is:

1. In. combination with a. cylinder and a piston adapted. for reciprocation therein and having an annular, parallel walled ring receiving groove, of a split metallic piston ring operatively disposed within said ring receiving groove, said piston ring'having a pair of spaced parallel outer cylindrical surfaces for contacting engagement with the cylinder wall and having an annular channel intermediate said pair of'outer contact faces, said annular channel having a pair of plane and parallel outermost side-walls and an inner wall portion of curved cross-section intermediate said outermost and parallel side-walls and spaced from said side-walls 'by corresponding connecting wall portions intermediate said plane parallel outermost side-walls and said inner wall of curved cross-section, said connecting wall portions extendlng transversely of sa1d outermost side-walls, and a series of comparatively small round holes extending from said inner annular channel through said ring, and a series of holes extending from the bottom of thering groove through the wall of the piston ;one of the side-contact surfaces of said piston ring having an area substantially less than the area of the other side-contact ceiving groove, said piston ring having a pair I of spaced parallel outer cylindrical surfaces for contacting engagementwith the cylinder wall and having an annular channel intermediatesaid pair of outer contact faces, said annular channel having a pair of plane and parallel outermost side-walls and an inner portion of curved cross-section intermediate said outermost and parallel side-walls,- and spaced from said side-walls by corresponding connecting wall portions intermediate said plane parallel outermost side walls and said inner wall of curved cross-section, said connecting wall portions extending transversely. of said outermost side-wall, and a series of comparatively small round holes extending from said inner annular channel through said ring, and a series of holes extending from the bottom of the ring groove through the wall of the piston, and means intermediate the inner wall of the ring-receiving groove and the piston ring for exerting a generally uniformly distributed outward radial pressure upon said ring whereby the two annular cylindrical contact surfaces of the piston ring are urged into contact with the cylinder wall and are caused to follow any slight irregularities of the same one of the side-contact surfacesof said piston ring having an area substantially less than the area of the other side-contact surface thereof. 1 J

3. In combination with a cylinder anda pistdn adapted for reciprocation therein and having an annular, parallel walled ring receiving groove, of a split metallic piston ring operatively disposed within said ring receiving groove, said piston ring having a pair of spaced parallel outercylindrical surfaces for contacting engagement withthe cylinder annular channel having a pair of plane and parallel outermost side-walls and an inner wall portion of curved cross-section intermediate said outermost and parallel side-walls and spaced from said side-walls by corresponding connecting wall portions intermediate said plane parallel outermost side-walls and said inner wall of curved cross-section said connecting wall portions extending transversely of said outermost side-walls, and a series of comparatively small round holes extending from said inner annular channel through said ring, and a series of holes extending from the bottom of the ring groove through the wall of the piston ;the upper side-contact surface of said piston ring having an area substantially less than the lower side-contact surface thereof.

4. In combination with a cylinder and a piston adapted for reciprocation therein and having an annular, parallel walled ring receiving groove, of a split metallic piston ring cooperatively disposed within said ring receiving groove, said piston ring having a pair of spaced parallel outer cylindrical surfaces for contacting engagement with the cylinder wall and having an annular channel intermediate said pair of outer contact faces, said annular channel having a pair of plane and parallel outermost side-walls and an inner portion of curved cross-section intermediate said outermost and parallel side-walls, and spaced from said side-walls by corresponding connecting wall portions intermediate said plane parallel outermost side walls and said inner wall of curved cross-section, said connecting wall portions extending transversely of said outermost side-wall, and a series of comparatively small round holes extending from said inner annular channel through said ring, and a series of holes extending from the bottom of the ring groove through the wall of the piston, and means intermediate the inner wall of the ring-receiving groove and the piston ring for exerting a generally uniformly distributed outward radial pressure upon said ring whereby the two annular cylindrical contactsurfaces of the piston ring are urged intocontact with the cylinder wall and are caused to follow any slight irregularities of the same ;--the upper side-contactsurface of said piston ring having an area substantially less than the lower side-contact surface thereof.

In testimony whereof I have hereunto set 5 my hand this 26th day of Sept, 1930.

FREDERICK W. WILKENING.