US3811690A - Seal - Google Patents

Abstract

An improved seal primarily for piston ring use wherein leakage is minimized by means of a seal member overlaying the end gap of the ring member and a ridge on the ring member to prevent flow of fluids past the end portion of the seal member. Fast seating, low friction, and long life are provided by selection of materials and dimensions.

Description

United States Patent [191 Moriarty May 21, 1974 SEAL I [76] Inventor: Maurice J. Moriarty, 3225 W. Primary Examl'fer f Sahuaro Dr. Phoenix Ariz 85028 Assistant Exammer-Robert I. Smlth v Attorney, Agent, or Firm-William H. Drummond; [22] Flledi Sept. 25, 1972 Don J, Flickinger [21] Appl. No.: 291,756

Related US. Application Data [63] Continuation of Ser. No. 66,333, Aug. 24, I970, [57] ABSTRACT abandoned An improved seal primarily for piston ring use wherein leakage is minimized by means of a seal member over- (gl. 277ll93ii267 7g2/ig laying the end gap of the ring member and a ridge on 58] Fie'ld 921494 the ring member to prevent flow of fluids past the end 165 195 portion of the seal member. Fast seating, low friction, and long life are provided by selection of materials [56] References Cited and dlmenslons' I UNITED STATES PATENTS 2 Claims, 13 Drawing Figures l,999,466 4/1935 Leonard 277/218 PATENTEDMAYZ] i974 3,811,690

sum 1 or 3 INVENTOR.

FIG. 6 higun'ce J. Moricrry ATTORNEY SHEETZUFS rm mEm-mm 19w:

INVENTOR: MOUHCS J. MOHGR'TY BY FIG.

- i g' eww ATTORNEY SEAL This application is a continuing application of my prior application Ser. No. 66,333 filed Aug. 24, 1970 on Improved Seal and now abandoned.

BACKGROUND OF THE INVENTION This invention relates to an improved seal.

More particularly, it relates primarily to shaft or cylinder type seals, especially piston rings.

In a further aspect, the invention concerns a seal of the above type which eliminates or minimizes flow of fluids past the seal.

In seal applications of the type having similar problems to piston rings in internal combustion engine applications, it is highly important to minimize the flow of fluids past the seal. In internal combustion engines, flow past the piston rings during the compression cycle not only lowers the effective compression obtained in the cylinder, but also allows raw fuel mixture to enter the crankcase, and either creates additional pollution and efficiency problems or requires the use of additional equipment to re-cycle the unburned fuel. Leakage during the combustion cycle not only detracts from power and efficient combustion, but also, similarly, produces crankcase emissions and pollution and recycling problems to handle.

Piston rings in use "today are not continuous seals but have an open junction known in the industry as the end-gap of the ring. Flow through the end-gap is, of course, related to the dimensions of the gap. Within v practical limits an effort is made in the industry to miniend-gap becomes wider and flow of fluids through the end-gap eventually reaches a magnitude where it becomes imperative to replace the piston ring.

The use of such seals in most applications is of such frequency and magnitude that economic practicability is of extreme importance. In the past attempts have been made to minimize the end-gap problems by use of a multiple number of rings with the respective end-gaps of the rings in a baffle type alignment, but the use of additional seals not only increases cost but also adds to the operating friction of the assembly, which is undesirable. Past techniques for elimination or drastically minimizing the end-gap have been unworkable grossly uneconomical, or have required the use of materials unsuited for many uses and not standard in the industry.

In addition to the mentioned problem of the leakage rate of present piston rings continuously increasing during the life of the ring, dimensional differences. in the ring because of its temperature produce such problems as extreme leakage through the end-gap at certain times, such as cold starting. Additionally, it is very important in providing a solution for the mentioned endgap problems not only to maintain the required material and cost design flexibility, but also to maintain or improve other desired features of present piston rings such as their necessary spring capability, the provisions for gaspressure loading of the seal, low friction, long wear life, and early seating.

It would be highly advantageous, therefore, to provide an improved seal in which end-gap leakage is ef fectively eliminated or minimized by constructions adaptable to the desired materials and which are completely economically feasible.

SUMMARY OF THE INVENTION Accordingly, it is a principal object and feature of the present invention to provide an improved seal without end-gap leakage.

Another object and feature of the present invention is to provide a piston ring with improved sealing capability.

A further object and feature of the present invention is the provision of a piston ring type seal which has extreme design flexibility in selection of desired materials, has ecomonic feasibility, easy seating, long life, and low friction.

Yet another object and feature of this invention is to provide an improved piston ring capable of obtaining a small, relatively constant leakage rate over the entire life of the ring.

Also, an additional object and feature of the present invention is to provide sufficient design flexibility so that the seal may be either pressure loaded or not, depending upon the desired application, and where such loading may be done in a desired direction.

A still further object and feature of the invention is to provide an effective piston ring throughout an extreme temperature range.

An additional object and feature of this invention is to provide a piston ring type seal which is so effective that only one seal need by used in applications where multiple rings are currently standard, thus reducing operationg friction.

Briefly, to accomplish the desired objectives of my present invention, in accordance with a preferred embodiment thereof, I first provide a piston ring member of relatively standard construction except that it contains a flat annular notch around a comer of the ring. An annular gap seal member dimensionally adapted to fit in said notch is located in the notch and overlays the end-gap of the piston ring to provide continuous sealing capability against blow by around the entire periphery of the ring. The material of the ring adjacent the notch provides a ridge which prevents gases from getting by my improved seal by means of entering the ring land area through the end-gap of the ring and exiting therefrom past the end of the gap seal member, since the ridge blocks the gases in the ring land area and does not allow further passage. These trapped pressures in the ring land area may be allowed to enter this area, however, for the purposes of providing gas pressure loading of the piston rings.

Additional preferred embodiments of the present invention allow the prevention of such gas pressure loading if not desired and further provide systems for securing gas pressure loading seal capability with pressure in either direction, as for example the providing of efficient sealing during both the compression and intake cycles of an internal combustion engine, where the directions of pressure are opposite during these respective cycles.

A highly preferred embodiment is one in which the gap seal member is substantially harder with respect to friction wear than the ring member, providing low friction and long life. Additionally, if the annular thickness of the gap seal member is made less than the annular thickness of the ring member notch, easy and rapid seating of the seal is obtained without loss of good long term wear characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS Further and more specific objects, features and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description thereof, taken in conjunction with the drawings, in which:

FIG. 1 is an upper perspective view of a piston ring of present design.

FIG. 2 is a partial perspective view, partially in section, showing the end-gap portion of a present piston ring in a ring land of a piston encased in a cylinder and illustrating blow by gas flow.

FIG. 3 is an upper exploded perspective view of a preferred embodiment of the present invention.

, FIG. 4 is an upper perspective view of the embodiment of FIG. 3 in assembled condition.

FIG. 5 is a partial perspective view, partially in section, showing the embodiment of FIG. 3 in a ring land of a piston encased in a cylinder and illustrating the effective blockage of gas flow.

FIG. 6 is an exploded partial perspective view of another preferred embodiment of the-present invention.

FIG. 7 is a partial perspective view, partially in section, illustrating yet another preferred embodiment of the present invention.

FIG. 8 is a partial perspective view, partially in section, illustrating yet an additional preferred embodiment of the present invention.

FIG. 9 is an exploded partial perspective view illustrating yet another preferred embodiment of the present invention as a modification of the embodiment of FIG. 3.

FIG. 10 is a partial perspective view, partially in section, illustrating yet an additional preferred embodiment of the present invention.

FIG. 11 is a partial perspective view, partially in section, similar to FIG. 5, but illustrating a highly preferred embodiment of the present invention, in conjunction with FIGS. 12 and 13.

FIG. 12 is a sectional view through the section l2-12 of FIG. 11, illustrating said highly preferred embodiment shortly after installation of the piston ring.

FIG. 13 is the same view as FIG. 12, but illustrates said highly preferred embodiment after the initial seating period.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Turning now to the drawings, in which the same reference numerals indicate corresponding elements throughout the several views, FIG. 1 illustrates a piston ring 21 of the type presently being used commercially. The end-gap 22 allows the ring to be mounted in ring land of the piston and then compressed into place so that bearing surface 23 is urged by the spring loading of compressed piston ring 21 against the cylinder wall. (In the present drawings the relative sizes of the various end-gaps shown are magnified for ease of understanding, over what these end-gaps would normally be when the piston rings are in their compressed state.)

FIG. 2 illustrates a piston 24 having a piston ring land 25. Piston 24 is encased in cylinder 26 and a portion of combustion chamber 27 is shown in the area above the upper surface 28 of piston 24. Arrow 29 illustrates the direction of gas pressure and flow through end-gap 22 of commercial piston ring 21 (shown mounted in piston ring land 25) during the compression, combustion and exhaust cycles. This flow, in addition to any gas flow between bearing surface 23 and cylinder 26, is known in the art as blow-by.

FIG. 3 illustrates a presently preferred embodiment of the present invention prior to assembly. Ring member 30 is similar to piston ring 21 but having certain modifications as hereinafter described. Shown below ring member 30 is a gap seal member 31. Ring member 30 has an end-gap 32 therein and a continuous cylindrical notch 33 (shown around the lower, outer portion of ring member 30) therein of a size to accommodate gap seal member 31. Gap seal member 31 contains end-gap 34.

FIG. 4 illustrates the embodiment of FIG. 3 after assembly. Notch 33 as shown includes a horizontal surface 35 and a vertical surface 36. Gap seal member 31 includes an internal surface 37 and an upper horizontal surface 38. When assembled, the bearing surface of this described preferred embodiment consists of bearing surface 39 of ring member 30 and bearing surface 40 of gap seal member 31. In use, bearing surfaces 39 and 40 are in contact with the cylinder wall. When so assembled, internal surface 41 of ring member 30 becomes the intemal surface of the entire assembled piston ring 42. The arrow 43 illustrates the path and direction of gas pressure of flow through the ring 42. It is noted that the end-gap has been eliminated and, although in the first instance gas is free to flow through end-gap 32 to the internal surfaces of piston ring 42, the gas path is then effectively block by surface 41 and cannot escape to the area beneath ring 42 through endgap 34.

The described blockage of blow-by is clearly illustrated in FIG. 5 wherein the preferred embodiment as described and shown is installed in a piston in a similar view to that of FIG. 2. Arrow 44 indicates the direction of gas pressure and the effective stoppage of blow-by.

FIG. 6 illustrates another embodiment of the present invention and shows a portion of improved piston ring 45. Piston ring 45 has two parts, ring member 46 and gap seal member 47. The portion of ring member 46 not illustrated is merely a continuous portion of ring as in a standard piston ring. Cylindrical notch 48 having end surfaces 49 is located in the upper outer portion of ring member 46. Gap seal member 47 (substantially a segment of an annulus in shape) fits within notch 48 and is free to move circularly therein. The ends 50 of gap seal member 47 contact the end surfaces 49 of notch 48 to prevent excess movement of gap seal member 47, thus ensuring that end-gap 51 of ring member 46 is covered to prevent blow-by at all times in similar manner to the embodiment of FIG. 3 described above. Although the embodiment of FIG. 6 retains the many discovered technical and performance advantages of multiple-piece construction, the embodiment of FIG. 6, not only in terms of performance but for the many obvious cost and manufacturing advantages inherent in such construction.

FIG. 7 illustrates an alternate construction of another preferred embodiment, similar to the embodiment of FIG. 3 but being a three piece structure. The improved piston ring assembly 52 includes ring member 53, upper gap seal member 54 and lower gap seal member 55. Gap seal member 54 and 55 are similar in construction to gap seal member 31. Ring member 53 includes both upper and lower cylindrical notches to receive gap seal members 54 and 55 as illustrated. Although the gas pressure loading characteristics of the embodiment of FIG. 7 are not as good as the embodiments described hereinbefore, such embodiments efficiently seal blowby in either direction of pressure in applications where the same is important.

FIG. 8 illustrates another improved piston ring assembly embodiment 56, having similar operation characteristics to the embodiment of FIG. 7 but construction more similar to FIG. 6. Piston ring 56 includes ring member 57 having an end-gap 58 therein, upper gap seal member 59 located in upper notch 60 of ring member 57, and lower gap seal member 61 located in lower notch 62 of ring member 57.

FIG. 9 shows a modified structure of the embodiment of FIG. 3 and includes modifications both to ring member 30 and gap seal member 31. It is important in the present invention that there be no alignment of end-gap 34 of gap seal member 31 and end-gap 32 of ring member 30. Furthermore, it has been found that for ease of assembly and operation the relative spacing of said end-gap one from the other is a factor preferable to be controlled, primarily to maximize spring expansion characteristics. In the illustrated preferred embodiment for setting and controlling the same, a tab 63 is located on gap seal member 31 at the preferred spacing from end'gap 34. Tab retainer notches 64 are located at both ends of end-gap 32 on the upper portion of the internal survace of ring member 30 as shown to receive tab 63. The presently preferred spacing of said end-gaps is approximately 45. The end-gaps should obviously not overlap and the'preferred upper limit of such spacing is 90.

FIG. is a view similar to the views of FIG. 2 and FIG. 5 illustrating a preferred embodiment of the present invention residing in the relative structure and location of the parts shown. Beneath piston ring land 25, carrying piston ring 42, is shown lower piston ring 65 in piston ring land 66. Piston ring 65 is like piston ring 42 except that it is placed in piston ring land 66 in an upside soen position to the placement of piston ring 42. To illustrate one advantage of this arrangement, arrow 67 shows the direction of pressure and gas glow from combustion chamber 27 during the compression, combustion and exhaust cycles of a four-cycle internal combustion process. Arrow 68 illustrates the direction of pressure and gas flow during the intake cycle. Thus, piston ring 42 is gas pressure loaded during the combustion, compression and exhaust cycles and piston ring 65 is similarly, because of its reversed position, gas pressure loaded during the same may be desired.

FIG. 11 illustrates, in a similar manner to FIG. 5, an embodiment of the type of FIG. 3 shown installed in piston 24 and bearing on the wall of cylinder 26. Gap

seal 31 is shown in position in ring member 30, in the surface with cylinder 26, and ring 30 may be cast iron.

FIG. 12 illustrates, by way of showing section 12-12 of FIG. 11, the detailed relationship of the parts during operation. FIG. 12 shows this particular cross section as it looks right after installation of the piston ring.

Ring member 30 is elastically expansive and there is bearing pressure being exerted along that portion of bearing surface 71 between ring member 30 and cylinder 26. Gap seal member 31 is slightly elastically expansive but not so much so as ring member 30. Thus, there is only a very slight bearing pressure along bearing surface between gap seal member 31 and cylinder 26. Surfaces 37 and 36 are not at this point touching since, for reasons to be hereinafter set out, the radial thickness of gap seal member 31 (that is the dis tance from surface 37 to surface 70) is made less than the radial thickness of the notch in ring member 30 (that is, distance between surface 36 and surface 70). Thus when the instant embodiment of the present invention is installed the primary bearing pressure and wear is occuring along bearing surface 71 and there is very little either friction or wear along bearing surface 70. According to the present invention the difference between the radial thickness of the gap seal member and the radial thickness of the ring member notch (shown in FIG. 12 as space 69) is made larger than the amount of material which must be worn off ring member 30 along bearing surface 71 in order to properly and adequately seat ring member 30 at said bearing surface 71. This distance will normally be set between one-thousandth of an inch and two-thousandths of an inch, and for the specific materials mentioned as preferred in this paragraph, the optimum dimensional difference, considering cost and production factors also, between the gap seal member anular thickness and the ring member notch anular thickness is approximately two-thousandths of an inch.

FIG. 13 illustrates the same embodiment along the same section as illustrated in FIG. 12, except that it.

shows the relationships among the parts when the initial seating of the seal of the present embodiment has taken place and surface 36 is riding along surface 37. At this point the outward radial bearing pressures of ring member 30 are transmitted by surface 36 at the ridge of ring member 30 to gap seal member 31. Since gap seal member 31 is substantially harder than ring member 30, a much larger unit bearing pressure is exerted along bearing surface 70 than along bearing surface 71. It is now seen that this highly preferred embodiment of the instant invention will have, during most of its life time, easy seating (not much friction initially at bearing surface 70), low friction (heavy unit bearing pressure only by the gap sea] member at surface 70 and very light contact at surface 71), excellent sealing (a large bearing contact area along bearing surface 71 maintained in good contact even at low pressure), excellent wear rate (the harder material of the gap seal member drastically slows down the rate of wear of the assembled piston ring), no decreaw in sealing performance with wear (where the gap seal member and ring member are both made of uniform materials, one would practically have to break or disintegrate the ring to get any appreciable deterioration in sealing with wear).

The sealing capabilities of the piston ring in the present invention are so much greater than those of standard piston rings that one piston ring will suffice in most applications with multiple piston rings are now being used. It is preferred, in the case of using a single piston ring, or for the case of the upper piston ring of several, that the gap seal member be located on the side of the ring member away from the combustion chamber, since the heat of the combustion chamber is better borne by the ring member. This is especially true when the ring member is composed of its preferred material, cast iron, and gap seal member is composed of its preferred material, steel (usually chrome plated).

Various changes in the embodiments herein chosen for purposes of illustration in the drawings will readily appear to persons skilled in the art having regard for the disclosure herein. To the extent that such modifications and variations do not depart form the spirit of the invention, they are intended to be included within the scope thereof which is not limited to the embodiments specifically illustrated, but rather only a fair interpretation of the following claims.

Having fully deccribed the invention in such manner as to enable those skilled in the art to understand and practice the same, l claim:

1. A piston ring assembly shaped and dimensioned to be received in a piston groove to provide an improved low-friction seal between said piston and the cooperating cylinder wall against the leakage of combustion gases generated in the combustion chamber above said piston and to maintain the effectiveness of said seal as the cylinder enlarges and distorts due to wear, said improved piston ring assembly comprising:

a. a severed annular. sealing ring, said ring member being elastically expansive to exert outwardly directed pressure against said cylinder wall; b. means defining a notch under the top surface of said sealing ring member, said notch having a horizontal surface extending radially inwardly from the periphery of said ring member and a vertical surface spaced from the inside diameter of said ring member; and c. a severed elastically expansive circular gap seal member sized to be received within said notch, said gap seal member having a radial thickness less than the horizontal distance of said notch the peripheral surface of said gap seal member being substantially more resistant to frictional wear than the peripheral surface of said ring member.

2. The piston ring assembly of claim 1, wherein said gap seal member is less elastically expansive than said seal ring member.

Claims (2)

1. A piston ring assembly shaped and dimensioned to be received in a piston groove to provide an improved low-friction seal between said piston and the cooperating cylinder wall against the leakage of combustion gases generated in the combustion chamber above said piston and to maintain the effectiveness of said seal as the cylinder enlarges and distorts due to wear, said improved piston ring assembly comprising: a. a severed annular sealing ring, said ring member being elastically expansive to exert outwardly directed pressure against said cylinder wall; b. means defining a notch under the top surface of said sealing ring member, said notch having a horizontal surface extending radially inwardly from the periphery of said ring member and a vertical surface spaced from the inside diameter of said ring member; and c. a severed elastically expansive circular gap seal member sized to be received within said notch, said gap seal member having a radial thickness less than the horizontal distance of said notch the peripheral surface of said gap seal member being substantially more resistant to frictional wear than the peripheral surface of said ring member.

2. The piston ring assembly of claim 1, wherein said gap seal member is less elastically expansive than said seal ring member.

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