RU2145018C1 - Builtup piston ring - Google Patents

Abstract

FIELD: piston apparatuses such as internal combustion engines, compressors and others. SUBSTANCE: builtup piston ring includes set of plate-type rings and bent as one piece tangential expander made of metallic rectangular cross section belt with rounded edges. Novelty is radial supporting flanges inclined one relative to another and relative to bridges joining them. Height of profile of tangential expander (according to its end abutments) is more than height of respective piston groove by 1.5 times or less. EFFECT: enhanced efficiency of oil scraping and compression properties of builtup piston ring, high reliability of operation of cylinder-piston group of engine, reduced consumption of fuel and lubricant materials, lowered quantity of harmful exhaust into environment. 7 dwg

Description

 The invention relates to mechanical engineering, namely to engine building, and can be used as a piston ring in internal combustion engines, compressors and other reciprocating machines.

 High demands are placed on piston rings for durability, ensuring a minimum oil consumption for burning, which determines the harmful emissions of solid particles into the atmosphere, gas breakthroughs and friction losses, which reduce fuel consumption. The number of piston rings on the piston should be minimal.

To meet these requirements, piston ring designs must have the following properties:
- high elasticity, ensuring the fit of the ring to the wall of the cylinder liner with distortions of its geometric shape;
- soft (gentle) characteristic of the spring of the tangential expander, providing a slight drop in the elastic force during wear of the friction elements of the ring;
- high resistance to the relaxation process in a non-stressed state at temperatures up to 300 ^o C;
- good collectability on the piston and together with the piston in the cylinder liner;
- Reliably seal the working space between the piston, cylinder and block head.

 A known design of a composite oil scraper ring (see invention according to copyright certificate N353058, M.cl. F 02 F 5/00: F 16 J 9/06), which contains two scraper rings and an integral curved tangential expander, radial shelves (protrusions) of which are placed between the rings perpendicular to the axis of the piston. In this case, the end stops can be made at right angles to the radial shelves or V-shaped, located in the same recesses of the rings.

 This instruction of a composite oil scraper ring does not fully meet the requirements for the following reasons. The ratio of the radial and axial loads on the rings, which is formed from the tangential force of the expander when compressing its turns, is practically not controllable, since the axial force is generated from turning the expander turns up and down when they are compressed during the installation of the piston with rings in the sleeve. If there is insufficient clearance between the ring and the piston groove, a sharp increase in axial force occurs and the rings partially or completely lose mobility in the piston groove, which impairs the fit of the rings to the cylinder wall, breaks the seal, and increases oil consumption due to its uneven distribution over the cylinder.

 With a large gap between the ring and the piston groove, the axial sealing of the piston ring groove is impaired, which reduces filling with the mixture during the suction cycle, reducing engine power.

 A composite piston ring is known (see RF patent N2028485 C1 6 F 02 F 5/00), which has both oil scraper and compression properties, which is closest to the invention in terms of technical nature and the achieved effect, and therefore is taken as a prototype. It consists of lamellar rings in the form of a packet of two or more and a whole curved tangential expander, in which the distance between the inner planes of the radial shelves is not more than the thickness of the metal tape from which it is made.

 Such a constructive implementation of the tangential expander most fully meets the requirements of a composite piston ring having oil scraper and compression properties, but the ratio of the radial and axial loads on the rings, which is formed from the tangential force of the expander, is almost not controllable during compression of its coils, despite the axial compensation efforts by the gap between the radial shelves, which are able to bend by the size of this gap between the radial shelves.

 At the same time, it should be noted that with a gap between radial shelves equal to or less than the thickness of the tape, the turns of the tangential expander in the manufacturing process at the places of bending of the radial shelves have a significant thinning of the original tape thickness (up to 35%), since the bending radius is equal to half the thickness of the bent tape and less. This thinning of the thickness of the tape reduces the strength of the turns of the tangential expander, which perceive a cyclic load during the operation of the engine, and leads to breakdowns of the turns and, as a result, failure of the piston ring.

 The objective of the invention is to increase the efficiency of a composite piston ring with oil scraper and compression properties, by ensuring that the ring package fits radially to the cylinder wall and axially to the ends of the piston groove.

 The problem is achieved in that in a composite piston ring for internal combustion engines containing a package of plate rings and a spring tangential expander made integrally curved from a metal tape of rectangular cross section with rounded edges and equipped with radial support shelves having end stops and interconnected by jumpers , while the radial support shelves are made obliquely relative to each other and to the connecting jumpers in this way the profile height of the tangential expander end stops exceeds the height of the corresponding piston within the groove to 1.5 times.

 Such structural designs in a composite piston ring make it possible to securely press a package of plate rings with the necessary force to the ends of the piston groove and the cylinder wall, providing high strength of the turns of the tangential expander, which during the operation of the engine absorb a cyclic load.

 In the known technical solutions, no signs are found that are similar to the distinguishing features of the claimed invention.

In FIG. 1 shows a cross section of a composite piston ring assembly;
figure 2 is a part of a composite piston ring with plate rings in working condition, depicted in perspective;
in FIG. 3 - a metal tape of rectangular cross section with rounded edges, curved in the plane of its thickness S into a serpentine workpiece of radius R with a step t and a width B;
figure 4 - serpentine workpiece with bent end stops for plate rings in size h;
in FIG. 5 - section aa in figure 4;
in FIG. 6 - serpentine workpiece with bent end stops with a formed profile in size H, in which the radial shelves are made with an inclination to the jumpers;
in FIG. 7 is a section BB in FIG. 6.

 A composite piston ring for an internal combustion engine contains lamellar rings 1 and 2 and a tangential expander 3 made integrally curved from a metal tape of rectangular cross section with rounded edges and provided with radial support shelves 4 and 5 made with an inclination to the jumper 6 connecting them; end stops 7 and 8 are made on the opposite side of the radial support shelves 4 and 5, pressing the plate rings 1 and 2 against the cylinder wall 9, and the radial support shelves 4 and 5 press the plate rings 1 and 2 to the piston groove surfaces 10 and 11. When mounting the tangential expander 3 and plate rings 1 and 2 in the piston groove, the radial support flanges 4 and 5 are straightened, creating an axial load to press the package of plate rings 1 and 2 to the surfaces 10 and 11 of the piston groove.

 Depending on the height of the piston groove, the combustion process (diesel, carburetor, etc.) and the number of revolutions of the engine crankshaft, various combinations of the package (number) of plate rings with a tangential expander are possible, while the profile height H and the inclination of the radial support flanges are relative to each other and to the connecting jumper 6 of the tangential expander 3 are performed in accordance with the necessary axial load pressing packages of plate rings 1 and 2 to the surfaces 10 and 11 of the piston groove (figure 1).

 The tangential expander 3 (Fig. 1) is made of an elastic metal tape of rectangular cross section with rounded edges.

 A tape of thickness S bends on the rib as shown in Fig. 3, forming spring coils with a pitch t, a width B and a radius R, and then the workpiece with spring coils is bent sequentially, as shown in Figs. 4 - 5, forming thrust collars with a height h and further the inclination of the radial support flanges relative to each other and to the jumper in the size of the profile height H of FIGS. 6-7.

 The piston composite ring operates as follows. When the piston is reciprocating, the lamellar rings 1 and 2 are pressed by the end stops 7 and 8 and the radial support flanges 4 and 5 of the tangential expander 3 in the radial direction to the cylinder wall 9, and in the axial direction to the piston groove surfaces 10 and 11.

 As a result of using the invention, the economic effect is expected from a decrease in the number of rings on the piston, a decrease in fuel and engine oil consumption for waste, and also an increase in the durability of the cylinder-piston group of the internal combustion engine.

Claims (1)

 A composite piston ring for an internal combustion engine containing lamellar rings and a spring tangential expander, made integrally curved from a metal tape of rectangular cross section with rounded edges and radial support flanges with end stops connected by jumpers, characterized in that the radial support flanges of the tangential expander are made obliquely relative to each other and to the jumper connecting them to a size N at the end stops, exceeding the size height of the piston groove up to 1.5 times.

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