Title of Invention

OIL RING ASSEMBLY

Abstract

A four piece type oil ring assembly adapted to be fitted in an oil ring grooves of a piston disposed within a cylinder of internal combustion engine comprising: a top side rail and a bottom side rail, both in the form of a gapped flat annulus a spacer expander(2,14) in the form of a gapped annulus terminating at gap end lugs, said spacer expander also made of steel and also having humps(4) placed in radial direction, and characterized in a plate expander (5,19) in the form of a gapped annulus made of steel having radial humps(4), said plate expander supporting the spacer expandsr(2,14) at its outer diameter(20) and gripping the piston groove root diameter(13) at its inner diameter(21), said plate expander having radially protruding humps(4) disposed on its circumference thereof, said plate expander having a perimeter which is more than that of the spacer expander(2,14), said spacer expander(2,14) having lugs extending upward and downward from inner side of humps to engage the inner radial surfaces of top rail and bottom rail respectively, and positioned in between the said top rail and the said bottom rail, and said assembly having the lug ends of the spacer expander are butting, the spacer expander gap and the plate expander gap are diametrically opposite with respect to each other, the gap in the top side rail is approximately 45 degree left top plate expander gap ends, the gap in the bottom side rail is approximately 45 degree right of spacer expander.

Full Text

PMOR ART In automotive engines, the oil control ring maintains the oil film thiciiness on the cylinder wall by scraping the excess lube oil from the wall. Three piece steel oil control ringCTPR) is used in most of petrol engines because of its low tangential load and high conformability factor and to avoid vacuum oil consumption. This ring assembly comprises two side rails(1) that are Icept apart by one Spacer expander(2,14) as shown in Fig, 1. The two rails are pressed against the cylinder wall by means of a special shaped Spacer expander(2,14). The Spacer expander(2,14) has wide passages for draining excess lube oil. The mass of this ring is very less compared to its cast iron counter part. Two types of spacer expanders(2,14) are commonly used in gasoline engines. Depending upon the arrangement of humps(4) in the spacer expanders(2,14)» they are classified as TPR-H or TPR-S. In 'H' type, the humps(4) 9trt arranged in a horizontal portion i.e. axial direction, as illustrated in Fig.2. In 'S' type, these humps(4) are placed in radial direction i.e perpendicular to axis, as illustrated in Fig. 3. The mass of the latter is less compared to that of the former. The main characteristics of the Spacer expander(2^14) are Hump width(8), Hump height(7), Expander total width(5), Step on side face(9), Tab seat angle(6), Vent(10) and Joint holes. The details are illustrated in Fig.4. The side r8ils(1) are pushed towards the cylinder bore by means of the spring pad(ll) portion of Spacer expander(2,14), which is inclined in such a fashion so as to give optimum tangential force. The spacer expander gap end lugs(3) should touch each other at right angles and form a butt joint as illustrated in Fig 5. Any overlapping of the gap end lugs(3) of TPR-S Spacer expander(2,14) will mal(e the whole oil ring assembly an inert ring. The conformity to the cylinder bore will not be there in such rings due to poor tangential load leading to high lube oil consumptton during engine run. Rings with an assembly width of 2.5mm and more than that are bolted with a latch pin(12) to avoid overlapping of Spacer expander(2,14) lugs. This latch pin(12) is made up of steel and inserted into the holes provided in the spacer expander humps(4) and lugs ends(3) as illustrated in Fig.6. It is known in prior art that there is a tendency for the oil rings to move circumferentially so that the oil ring gaps align with each other and frequently with the gap of the space expander. In such a situation, oil consumption is increased. There is also a need to lock the rotation of each rail relative to spacer expander in an installed staggered circumferential orientation, which is achieved by TPR - H or TPR -S type space expander. DISADVANTAGES IN PRIOR ART TPR-S Oil rings with an assembly width of less than 2.5mm are plain without any holes on Spacer expander(2,14) due to strength considerations and hence no latch pin is provided. So the gap end lugs(3) of Spacer expander(2,14) are highly prone to overlapping during engine assembly. To overcome this problem, a high degree of care is being talcen during piston ring assembly into the cylinder. Despite this, some expanders get assembled with overlapped lugs, which mai(e the ring assembly ineffective and leads to increased lube oil consumption. Sometimes this overlapping problem ends up in lug brealtage. The main reason for overlapping of gap end lug$(3) is because the baci( clearance (piston groove root diameter(13) to ring inner diameter(21)) of TPR-S type oil ring is higher, causing the lug ends(3) to move freely over each other as illustrated in Fig. 7. The swinginc distance of lugs +tlie perimeter of spacer expander >the perimeter of piston groove root diameter. OBJECT OF THE INVENTION It is to be noted that though TPR • S expander is good in performance, the problem of gap and lugs overlapping is a problem, which needs attention for better performance of the oil ring assembly. This is the prime object of this invention. Piston oil assembly including the Spacer expander(2,14) has given good results in terms of lube oil consumption. {However, when the lug ends(3) of the Spacer expander(2,14) are overlapped, the self-expanding function of the Spacer expander(2,14) is lowered. This because when the gap ends(3) are overlapped together, the naturally radially outward expanding force of the Spacer expander(2,14) is lost and hence the Spacer expander(2,14) cannot transmit its tension force to the side raiis(l). As a result, lube oil loss is increased. As such it has been attempted in this invention to prevent the lug ends(3) of the spacer-expander(2) from overlapping. The excess baci( clearance has to be reduced in order to avoid overlapping of spacer expander lugs. This can be achieved in the existing setup by the following ways:- a. The groove root diameter can be adjusted to an optimum level, but this puts restraints on the manufactinrabiUty of the piston and piston rings because of closer tolerances of the individual components of the assembly. Normally oil control rings are operated at higher bacl( clearances. Hence this solution is impracticable. b. The TPR-S expander radial thicicness may be increased to fill up the clearance, but that will affect the confbnnability of the ring. As per the invention a bacf(up plate expander(15,19) has been used to fill up the buffer space in between groove root diameter and the TPR-S oil ring assembly to prevent overlapping of lugs as illustrated in Fig.8. Emptoyment of this plate expander(15,19) as per the invention further enables the piston assembly into the bore easier, the hump(4) arrangement of plate expander(15,19) ensures that there is never oil passage blocluge in the piston and furthermore there is no additional wear and tear problem due to this new arrangement. Accordingly an object of the present invention to eliminate the problem arising due to overlapped lugs of Spacer expander(2,14) which maices the ring assembly inert and lead to increased lube oil consumption. Overlapping lugs also tend to breal( at times. Accordingly in the present invention the foregoing object is attained by emptoying a fourth piece in the three piece oil ring assembly knoYtn as "Plate expander" which has a perimeter greater than perimeter of Spacer expander(2,14) and has radial humps(4). The inner diameter(21) of plate expander(15,19) grips the piston groove root diameter(13) while outer diameter(20) will supports the Spacer expander(2»14) and thereby plate expander(15,19) restricts the movement of lugs of Spacer expander(2,14}. SUMMARY OF THE INVENTION As per the invention the oil ring assembly comprises a four piece oil ring assembly consisting of a top side rail(16), bottom side rail(17), Spacer expander(2,14) and a plate expander(15»19). The plate expander(15,19) having a perimeter greater than perimeter of space expander(2,14) and having atleast 12 radial humps(4) and such that its inner diameter(21) grips piston groove root diameter(13) and outer dlameter(20) will support the space expander so as to prevent the overlapping of the lug ends(3). The top side rail(16) is seated on upper end surface of the Spacer expander(2,14) and bottom side rail(17) is seated on tower end surface of the Spacer expander(2,14) which Spacer expander(2,14) is fitted into the groove of a reciprocating piston of internal combustion engine. The outer peripheral edges of the side rails(l) will contact the inner wall of the cylinder and prevent leakage of oil due to a spring -like property of the Spacer expander(2»14). The assembly is illustrated as in Fig. 9. In fitted condition some clearance exists between ring assembly and plate expander(15,19), hence there is no wear and tear problem. The hump(4) arrangement of plate expander(15,19) will never btock the oil passage in the piston. This plate expander(15,19) as per this invention is made up of steel material and has at least 12 radial humps(4). The inner diameter(21) (ID) of this plate expander(15,19) will grip the piston groove root diameter(13) and the outer diameter(20) In accordance with the invention, the top and bottom rails make unifbnn contact with the inner wall of a cylinder over its entire circumference by virtue of the Spacer expander(2,14) along with plate expander(15,19). This makes it possible to improve oil scraping performance and to reduce the amount of lubricant consumed. The invention as such provides an improved four piece oil ring assembly by which the side rail(1) is always in operative contact with the inner surface of I cylinder even when the piston inclines to the cylinder at engine bnkt running and by which the side rail(l) follows the inner surface of cylinder even when the cylinder is defbnned at high speed running and further capable of reducing the oil consumption at engine bral(e running. This is ensured by achieving all - time self expanding function of the Spacer expander(2,14). It can thus be seen that through this invention a low cost solution for increased oil consumption has been provided which can be assembled readily and without any possibility of misassemble, and which would be effective in eliminating any possibility of alignment of the gaps of oil ring rails and the Spacer expander(2,14) and further prevent the overlapping of lug ends(3) of Spacer expander According to the present invention, the plate expander(15,19) is made of steel material and has at least twelve radial humps(4) as illustrated in Fig 10. Referring to Fig 8, the plate expander(15,19) is assembled with space expander(2,14) as illustrated in the drawing. DESCRIPTION OF PREFERRED EMBODIMENT The plate expander(15,19) of the four piece oil ring assembly to which the present invention has been applied has a configuration as illustrated in Fig 10. The novelty as per the invention is the use of at least 12 radial hump(4) expander as a bacl( up fbr the regular TPR-S rings and thus avoiding overlap of lug ends(3). As is clearly illustrated in Fig 8, the plate expander(15,19) fitted within the space expander prevents the overlapping of lug ends(3) of the space expander(2,14). The combination of pUte expander(15,19) and Spacer expander(2,14) as per the invention ensures the same level of control of lube oil consumption as in prior art using TPR -S rings as spacer expander(2,14) per se and further enhances the continuous good perfonnance of spacer expander(2,14) by eliminating the problem arising due to overlapping lugs which is inherent in prior art. The shape, configuration and size of the plate expander(15,19) as per the invention is well illustrated in Fig 10. The preferred material and composition of the invention includes material of type SUS 304 and the chemical composition {%) as detailed below :• CHEMICAL COMPOSITION (X) C Si Mn PJ S Ni Cr MIN ■" mm mm SUS304 MAX 0.08 1.00 2.00 0.045 0.030 10.50 20.00 According to this invention, an additional fourth unit is provided to the l(nown TPR-S assembly, which is a plate expander(15,19), in the form of gapped annulus made of steel, which is fitted within the spacer expander(2,14). The plate expander has at least twelve radial humps(4) radially distributed evenly along the circumference, the depth being less than spacer expander(2,14) width, thicicness range being 0.15 mm to 0.80 mm, inner diameter(21) is nearer to piston groove root diameter(13), outer diameter(20) is dependent on the inner diameter(21) of the spacer expander(2,14) the ends being free from burrs. The shape, size and configuration of the plate expander(15,19) as per the invention is well illustrated in fig 10. The construction for fitting of spacer expander(2,14) along with plate expander(15,19) and the top and bottom side rails(16,17) as per invention is as fbllows :• 1. Fit the plate expander(15,19) into the ring groove and ensure that the gap ends are facing as illustrated in fig. 11 2. Fit the spacer expander(2,14) into the ring groove and ensure that the lug ends(3) are butting as illustrated in fig. 12 (avoid overlapping of lugs as illustrated in fig. 13) 3. Hold with thumb the spacer expander(2,14) with lugs completely butting, install the upper side rail(16) with its gap approximately 45** left of plate expander ends. 4. install the lower side rail(17) with its gup approximately 45** right of spacer expander(2,14) ends. 5. Confirm the installation of piston ring by ensuring that the gap end is not located on the line of thrust side or piston pin axis. 6. Ensure that all gap ends are located as illustrated in fig. 11 BRIEF EXPUNATION OF THE DRAWINGS : The present invention may be more specifically understood from the following description of a preferred embodiment talien abng with accompanying drawings in which Fig 1 :- illustrates cross-sectional view of a spacer expander(2»14) which is placed in between the two side rails(1) of TPR assem bly. Fig 2 :- Illustrates a TPR - H spacer expander(2,14) in which the humps(4) are arranged in axial direction. Fig 3 :• Illustrates a TPR • S spacer expander(2,14) in which the humps(4) are arranged in radial direction. Fig 4 :• illustrates a cross section of TPR - S spacer expander(2,14) in which the main characteristics of this spacer expander(2,14) are mentioned. Fig 5 :-IUustrates an exploded view of portion of spacer expander(2,14) In which the gap end lugs(3) are touched at right angles to form a butt joint. Fig 6 :-illustrates a latch pin which is inserted into the holes provided in the spacer expander humps(4) and lug ends(3) in case of rings with an assembly width of 2.5 mm and more. Fig 7:- illustrates the overlapping of expander gap end lugs(3) to form an inert ring - an inherent problem found in prior art. Fig 8 :- illustrates the positioning and fixing of plate expander(15,19) along with spacer expander(2,14) to prevent the overlapping of lug ends(3) In oil ring assembly as per this invention. Fig 9 :• illustrates a four piece oil ring assembly illustrating the plate expander(15,19), with Top side rail(16), bottom side rail(17) and Spacer expander(2,14). Fig 10 :- illustrates the configuration of the plate expander(15,19) of present invention comprising four piece oil ring assembly. Fig 11 :• illustrates the sUggering of ring joints to ensure the upper side rail(16) of spacer expander(2,14) is 45 *> left of the plate expander(15,19) ends as per this invention. Fig 12 :- illustrates the spacer expander gap(23) end position wherein the lug ends(3) are butting as preferred without overlapping. Fig 13 :- illustrates lug ends(3) of spacer expander(2,14) wherein the lugs are overlapped and is not desired. Reference Numerals in the drawings : 1 Side rail 2,14 Spacer expander 3 Gap end lug 4 Fiump 5 Expander width 6 Tab seat angle 7 Hump height 8 Hump width 9 Step on side face 10 Vent hole 11 Spring pad 12 Latch pin 13 Piston groove root diam eter 15,19 Plate expander 16 Top side rail 17 Bottom side rail 18 Spacer expander'S' type 20 Outer diameter 21 Inner diameter 22 Plate expander thici^ness 23 Spacer expander gap 24 Bottom rail gap 25 Plate expander gap 26 Top rail gap 27 Exhaust side As many embodiments of plate expander covered in this invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as covered in the claims. WE CLAIM : 1. A four piece type oil riiig assembly adapted to be fitted in mx oil ring gx'ooves of a piston disposed witliin a cylinder of internal combustion engine comprising:- - a top side rail and a bottom side rail, both in the form of a gapped flat iannulus a spacer expander(2>14) in the form of a gapped anniikis terminating at gap end lugs, s^aid spacer expander al^o made of steel and also having humps(4) placed in radial direction, and characterized in a plate expander (v55l9) in the form of a gapped aniiulus made of steel having radial humps(4), - ^iaid plate exjjaiider supporting the si)acer «5X{)aiider(2,14) at its outer diameter(20) aiid gripping the piston groove root diameter(13) at its inner diam.eter(21) > - said plate expander having radially protioiding hum.ps(4) disposed oti its drcumference thereof, - said plate ex|?aiider liaving a perimeter wliich is more than tiiat of the spacer expander(2 ^ 14), - said spacer expander(2,14) having lugs extending upward and downward from inner side of humps to engage the inner radial surfaces of top r^iil and bottom rail respectively^ and positioned iii between the said top rail and the said bottom rail^ and - said assembly having the lug ends of the spacer expander are butting, the spacer expander gap and tlie plate expander gap ai-e diametrically opposite with respect to each other, the gap in. the top side rail is approximately 45^ loft top plate expander gap ends, the gap iii the bottom aide rail is approximately 45^ right of spacer expander. 2. A four piec 3. A four piece type oil ring assembly adapted to be fitted in an oil ring grooves of a piston disposed mthin a cylinder ot internal combustion engine aa claimed in claim 1, \i^herein the depth of tlie said t^Vftti^ ^VT\ftr\^^*:*f ■>^ 4. A four piece tyj>e oil rbig assembly adapted to be fitted m an oil ring grooves of a pifitoii disposed mtlitri a cyhnder of interna! combustion etigirie as claimed m ci^im. U wherein, the tliickness of the said plate expander is betw^een 0.15 to 0.80 mxa. 5. A four piece type oil ring assembly adapted to be fitted in an oil ring grooves of a pifiton dispo sed mthin a cylinder of internal combustion engine as claimed in. claim 1. wherein the inner diameter of the ?*aid plate exi>ander m equal to or aiouud tire piston groove root \.*JLit,*xii.»j'i.ex (M.*^t 6. A four piece type oil ring assembly adapted to be fitted m axi oil ring grooves of a piston disposed x^dtliin a cylinder of internal cotubustion engine as claimed in claim 1, wherein the ovitet cUameter(20) of the said plate expander is less tliaii or equal to tlie spacer exi:>6jider inner diameter. 7. A four piece type oil ring assembly adapted to be fitted in en oil ring grooves of a piston disposed witMn a cylinder of internal combustion engine as claimed in claim I, wherein the material of tkm plate es^jander is steeL

Documents:

0618-che-2004 claims duplicate.pdf

0618-che-2004 description (complete) duplicate.pdf

618-che-2004-claims.pdf

618-che-2004-correspondnece-others.pdf

618-che-2004-correspondnece-po.pdf

618-che-2004-description(complete).pdf

618-che-2004-drawings.pdf

618-che-2004-form 1.pdf

618-che-2004-form 19.pdf

618-che-2004-form 26.pdf

618-che-2004-form 3.pdf

618-che-2004-form 5.pdf