US2170970A

US2170970A - Piston, ring, and ring expander

Info

Publication number: US2170970A
Application number: US142851A
Authority: US
Inventors: Charles F Johnston
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-05-15
Filing date: 1937-05-15
Publication date: 1939-08-29
Anticipated expiration: 1956-08-29

Description

Aug. 29, 1939. C, F. JQHNSTQN 2,170,970

PISTON. RING, AND RING EXPANDER Filed lay 15, 1937 F1553; f/ fifa /za A :l INVENTOR Hgo/7 /0/7. BY

ATTORNEY.

Patented ug. 29, 1939 UNITED STATES lPATENT OFFICE 2,170,970 rrs'roN, RING, AND RING EXPANDER Charles F. Johnston, Oakland, Calif. Application May 15, 1937, serial No. 142,351

6 Claims.

The invention relates to pistons such as used in internal combustion engines and which may have incorporated therewith piston rings and ring expander means.

An object of the invention is to provide in a piston, rings and expander combination of the character described an improved form and construction affording a. greatly improved life of the expander.

Another object of the invention is to provide in a combination of the character described for a material strengthening of the support for the free ends of the ring accomplishing `a substantially complete elimination of so-called ring flutter or destructive vibration of the free ends of the ring.

A further object of the invention is to provide l an improved ventilated oil ring affording a highv ly efficient oil lcontrol and improved oil passage constructions and being Aeffective to substantially eliminate the possibility of vclogging ofthe oil passages by the accumulation of carbon deposits on the ring.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forthfin the following 'description of the preferred form of the invention which is illustrated in the drawing accompanying and forming part of the specication. It is to be understood, however, that variations in the showing made by the said drawing and description may be adopted within the scope of the invention as set forth in the claims.

Referring to said drawing:

Figure 1 is a plan sectional View of a piston, ring and ring expander combination constructed in accordance with the present invention.

Figure 2 is ka fragmentary vertical sectional view of the combination shown in Figure 1.

' Figure 3 is a View similar to Figure 2. but showing a different section of the ring and with the latter compressed in a cylinder.

Figure 4 is a vertical elevation of the combina tion illustrated in Figure 1. g,

Figure 5 is a fragmentary sectional view similar to Figure 2, but showing a modified form of the invention.

, Figure 6 is a plan view of the expander illustrated in Figure 4.

Figure 7 is a fragmentary cross sectional view of the expander illustrated in Figure `6 and is taken substantially on the plane of line l--l of` Figure 6.

Figure 8 is a fragmentary cross sectional view 55 of the expander illustrated in Figure 6 and is' taken substantially upon the plane of line 8 8 of Figure 6.

The invention, as illustrated in the accompanying drawing, consists of a piston 8 which is provided with a plurality of longitudinally spaced 5 annular ring grooves 9 which are each adapted for the receipt of a piston ring II. In accordance with the present arrangement a spring expander member I2 is mounted in the ring groove 9 behind the ring II so as to engage between the 10 base I3 of the groove and the inner face I4 of the ring to resiliently urge the latter to an outward expanded position against the cylinder side wall with which the piston is used. The expander I2 is preferably constructed of an elonl5 gated strip of resilient material which is bent into a generally annular slnuous form so as to occupy a minimum amount of space when compressed between the ring and the base of the ring groove and yet provide a substantial amount 20 of resilience for urging the ring to an expanded position.

Heretoforeit has been the practice to engage the fiat sides of the expander spring with corresponding iiat sides at the base of the ring groove and at the inner face of the ring. As a result the spring, after a relatively short length of time, Was Worn thin at its points of contact with the ringA and the groove base and after a short periodV of use the spring would fail. In accordance with the present invention and as a principal object thereof, I have so designed the form of the piston groove and the spring and the ring so as to very greatly increase the life of the spring. In the present showing this construction is such as to cause the engagement of the spring between the base of the ring groove and the inner face of the ring exclusively at the side edges of the strip which comprises the spring so that the strip has its entire width disposed in the direction of wear as contrasted to the former arrangement wherein only the relatively thin side wall of the strip was in the direction of wear. In the form of the invention illustrated in Figures 1-4 the base I3 of the groove and the inner face I4 of the ring are 45 provided with recesses receding away from the spring so as to allow the entry of the spring into the recesses and the latter are so formed as to engage the spring exclusively at the top and bottom edges I 6 and I1 of the spring. As will be 50 seen from Figures 1-4 the recesses in the base I3 and the ring side I4 each taper away from the spring I2, the recess in the groove base I3 consisting of a pair of tapered sides I8 and I9 which extend from the upper and lower ring lands 2| 55 and 22 of the groove, while the recess provided in the side I4 of the ring consists of a pair of

tapered sides

23 and 24 which, as in the case of the recessed sides I8 and I9, engage the expander spring exclusively at the top and bottom sides I6 and I1 thereof. As another important feature of this construction, it will be noted that due to the sinuous or polygonal shape of the expander spring, any wear of the side edges I6 and I1 at the surfaces I8, |9, 23 and 24 allows the spring to work its way further into the recesses and thereby increases the wearing area on the spring. While the recesses are here shown tapered it will be understood that the same may be rounded or otherwise curved so as to exclusively engage the top and bottom surfaces of the spring. y In the form of the invention illustrated in Figures 5-8 the arrangement for providing for the wear on the spring exclusively at the side edges thereof is effected by the construction of the spring itself. As here shown, a plurality of alternately spaced radially outwardly extending and radially inwardly extending projections 2B and 21 are formed on the top and bottom edges I6 and |1 of the ring I2 for engagement with the ring groove base and the inner periphery of the ring respectively. In this manner the wear on the spring is confined to the

projections

26 and 21 rather than across the full width of the expander spring. In accordance with the spring here shown the projections 26 are bent outwardly from the body of the strip forming the spring I2 at the corners 28 of the polygon formed by the spring while the projections 21 are pressed inwardly at an intermediate portion of the sides 29 of the polygon intermediate the corners 28.

As another important feature of the present invention both of the spring expanders I2 and I2', illustrated in the accompanying drawing, are arranged in a sinuous or polygonal shape with the outstanding corners 28 and the intermediate sides 29 which are engaged with the inner face of the ring and the base of the ring groove respectively. As will be seen particularly from Figure 1, the sides 29 of the polygon are substantially tangential to the inscribed circle formed by the base of the ring groove in the piston and the free ends 3| and 32 of the spring are' formed as abbreviated side portions which extend substantially to the inscribed circle and are substantially tangential with respect thereto. This construction is of great importance in rendering uniform the resilience of the expander around the periphery thereof and providing a uniform support for the piston ring. As Will be seen from Figure 1, the engagement of the free end portions 3| and 32 with the base of the piston groove gives the adjacent corner portions 28 of the spring a double support against the base of the ring groove 9 at the end portions 3| and 32 and the other at the next adjacent side 29 to the corners 28'. In assembling the ring I prefer to arrange the free end portions 3| and 32 of the spring opposite to the

free ends

33 and 34 of the ring so as to afford these free ends of the ring a maximum support and to securely hold the latter against destructive vibration or so-called "ring flutter". As will be further understood, the extension of the free ends 3| and 32 of the spring substantially to and tangential with the base of the ring groove, causes these free end portions to constantly hug the base of the ring groove in all positions of relative compression of the spring and at no time is it possible for the free ends of the spring to Work or find their Way through the free ends of the ring and thereby become exposed at the cylinder wall whereconsiderable damage may be done by way of scratching or scoring the cylinder wall. Insofar as I am aware, it has been heretofore the practice of leaving the free ends of the spring removed by a considerable distance fromthe base of the ring groove so that frequently in the assembling of the rings one of the spring ends would become positioned between the ends of the ring and on subsequent compression preparatory to insertion in a cylinder a mutilation or breaking of the expander spring .substantially entirely prevent the clogging of the oil passage therethrough by the accumulation of carbon deposits on the ring. The ring is provided around the outer periphery 36 with a relatively wide channel 31 which defines at the upper and lower portions of the periphery a pair of axially spaced annular portions or

shoulders

38 and 39 which provide for an efficient wiping'of the oil off from the cylinder side wall and at the same time the size of the channel 31 affords an abundant oil capacity for the transfer-of oil onto and the removal of oil from the cylinder side wall. 'Ihe oil is afforded passage from the channel 31 into the ring groove 9 and vice versa by way of a plurality of slots 4| which are formed in the ring in circumferentially spaced relation around the ring. The

tapered sides

23 and 24 on the inner face I4 of the ring, in accordance with the present invention, extend from adjacent the top and`

bottom sides

42 and 43 of the ring at the inner periphery thereof to the slots 4| at a position spaced a substantial distance from the inner periphery of the ring. Thus, the smallness of the transverse o r radial dimension of the narrow portion of the slots is materially reduced and on the other hand,

the widening of the slots at the

sides

23 and 24 very materially enlarges the oil passage with the result that there is little or no opportunity for carbon deposits to-build up in the oil passage through the ring and obstruct or close oi the oil flow. It will also be noted that the extension of the

sides

23 and 24 from the inner periphery of the ring, in no way interferes with the full radial Width of the

sides

42 and 43 of the ring and leaves a full and efiicient engagement of these sides with the ring lands 2| and 22.

Passage of oil from the ring grooves 9 into the interior 44 of the piston is provided by way of a plurality of circumferentially spaced openings 46 formed through the piston Wall 41 at the base of each of the ring grooves supporting an oil ring.4

I claim:

1. In combination, apiston provided with an annular ring groove, a piston ring mounted in said groove, a fiat polygonal spring mounted between and engaged with the base of said groove and the inner face of said ring for expanding said ring in said groove, said groove base and said inner ring face being receded from each other so as to engage said spring exclusively at the side edges of said spring.

2. In combination, a piston having an annular ring groove, a piston ring mounted in said groove, and a fiat sinuous spring mounted between and engaged with the base of said groove and the inner face'of saidkring, said groove base and said ring face being provided with radially opposed tapered recesses receding from each other to engage said spring exclusively at the side edges thereof.

3. A piston provided with a ring groove adapted for receipt of a piston ring, and a flat sinuous spring engageable between the base of said groove and the inner facevof said ring for expanding the latter, said groove base being provided with a recess receding from said groove so as to engage the sides of said recess exclusively with the side edges of said spring.

4. A piston provided with a ring groove adapted for receipt of a piston ring, and a flat sinuous spring engageable between the base of said groove and the inner face of said ring for expanding the latter, said groove base being provided with a recess receding from said groove and provided with radial inwardly tapering sides adapted for engagement 1with said spring exclusively at the side edges of said spring.

5. An expansion spring for positioning between the base of al piston ring groove and the inner face of the piston ring for expanding the latter and comprising a iiat annular sinuous member provided with spaced radial inward projections extending from the at body of said member adjacent the inwardly disposed sinuous portions of the member and radially outward projections adjacent the outwardly disposed sinuous portions of the member adapted for engagement with said groove base and said ring face respectively to space the flat body of the member from the piston and the ring.

6. A flat polygonal expansion spring for positioning between the base of a piston ring groove,

v and the inner face of a piston ring mounted 'in said groove for expanding said ring, and having projections outwardly extended from the side edges thereof at the corners of the spring for' engagement with said groove base, and having projections inwardly extended from the side edges along the sides of the ring intermediate said corners for engagement with the inner face of said ring.

` CHARLES F. JOHNSTON.