KR830002246B1 - Polishing method of piston ring - Google Patents

Abstract

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Description

Polishing method of piston ring

1 is a plan view of a piston ring according to a salient feature of the invention.

2 is a front view of the piston ring of FIG.

3 is a cross sectional view of the piston ring shown in FIG. 1, taken along line 3-3 of FIG.

4 is a partially enlarged cross-sectional view of the piston ring shown in FIG. 1 and FIG.

5 is a schematic representation of an apparatus for forming the top or bottom wall shape of the piston ring shown in FIGS. 1-4.

6 is a partially enlarged cross-sectional view of a modified form of the piston-piston ring assembly shown in FIGS. 1, 2, 3, and 4;

7 is a perspective view of a modified form of the polishing apparatus for forming a piston ring according to the method of the present invention.

8 is a partially enlarged cross-sectional view of the ring holder of FIG.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for polishing a piston ring of Kystone type which is used as a compression ring of an engine and used for various engine applications. The purpose of such a ring is to achieve a seal of the space between the piston and the liner to prevent high pressure combustion gases or air charges from leaking in the liner during compression or backstroke, and to cool the cylinder liner from the piston It transfers heat energy and absorbs some of the piston side thrust fluctuations.

The internal combustion engine has a compression ring in which the bottom wall or both the bottom and top walls are inclined to form a thinner ring on the inside than at the outside diameter. The groove of the piston for receiving the ring is machined in the same overall form. The gas pressure acting on the top wall of the ring due to the inclined bottom surface generates additional forces that assist in urging the ring outwards against the cylinder wall and properly achieving the desired closure.

On the other hand, at each inversion of the lateral thrust of the piston, the ring slides slightly into the piston groove and is pressed against the upper groove wall and pulverizes the carbon deposited thereon to prevent the ring from sticking.

It is an object of the present invention to provide a piston ring structure for a fluid pressure device, wherein the sealing relationship between the ring and the piston is improved to achieve an airtight seal.

Another object of the invention is that line-to-line contact is achieved between the piston ring and the outer circumferential groove of the piston to prevent, for example, the combustion gas of the internal combustion engine from passing into the crankcase and oil into the combustion chamber. It is to provide a piston ring structure to prevent excessive passage.

It is a further object of the present invention that at least one wall of the piston ring is inclined inwardly and has a curved cross-section and the piston has a suitable shape to achieve a line-to-line contact between the curved surface of the ring and the outer edge of the piston groove. To provide a piston ring structure that cooperates with the groove of the.

Another object of the present invention is to provide a piston ring in which at least one of the curved facets has an inwardly inclined wall and can be easily and economically polished.

It is an object of the present invention to provide a method for polishing a piston ring having a wall in which at least one of the curved sections is machined inward.

Other objects and advantages of the present invention will become apparent from the following detailed description of one embodiment of the invention described with reference to the accompanying drawings.

The present invention relates to a piston ring which is a self-tensioned annular metal piece provided in a piston groove so as to provide a movable seal between a crankcase and a combustion chamber of an internal combustion engine and polishing of such a ring.

The metal used for the piston ring must meet a number of requirements. The metal should be a good bearing material and have a low wear rate. In some instances, the metal of the ring is covered with a material having such properties. In addition, the metal should be of moderate hardness, high strength, easy machinability, good elasticity and fatigue resistant. The ring material should be able to work under the condition of boundary lubrication while supporting high loads. The metal should almost retain its mechanical strength during operation at high temperatures and pressures of the engine. In addition, the hot corrosive combustion products should not have an extremely adverse effect on the wear properties of the metal of the ring.

Multiple coatings and platings may be applied to reduce wear of the piston ring and impart desirable properties thereto.

Some types of special facing or chemical treatments, such as, for example, thin bearing surfaces of frictional metal, facilitate the installation and use of new rings. Such face cutting is achieved by gradually grinding the surface of the ring and small rough grooves on the cylinder liner so that good surface-to-surface contact is achieved without excessive friction causing wear or damage.

All the various desirable properties of the piston ring material serve to provide the piston ring with a movable seal that prevents combustion gas from passing into the crankcase and excess oil from passing into the combustion chamber. This dual function has led to years of development of two basic piston ring types: compression rings and oil rings. Within their broad scope, hundreds of other structural changes have been developed. Suitable ring structures are typically combined in combination to provide the best, optimal performance for each engine under all operating conditions.

In Figures 1, 2, 3 and 4 there is shown a piston ring 10 according to the invention with a spacing 12. The ring 10 is a keystone having an outer circumferential wall 14, commonly referred to as a piston ring face, an inwardly reduced top wall 16, an inwardly reduced bottom wall 18, and an inner wall 20. It is called a type piston ring. The top wall 16 and the bottom wall 18 are formed to have a slightly concave cross section as shown in FIG. In FIG. 4 the piston ring 10 is shown housed in a groove 22 formed in the outer circumferential wall of the piston 24. The groove 22 is formed by the upper wall 26 reduced inwardly, the bottom wall 28 reduced inwardly, and the trailing wall 30. The piston 24 is adapted to reciprocate in the cylinder formed by the cylinder wall 32. The diameter of the ring 10 is slightly larger than the cylinder inner diameter in the free state, thus compressing the cylinder wall 32 of the engine when the ring is pressed into the cylinder to achieve a seal. This initial sealing action was greatly enhanced by the gas pressure of the engine during the compression stroke as shown in FIG. The pressure of the compressed air or compressed gas against the upper surface 16 of the ring 10 presses the ring downwards on the bottom wall 28 of the outer circumferential groove 22 of the piston 24 to radius the ring 10. There is a tendency to slide outward.

This creates a gap in the upper wall 16 of the ring such that gas pressure passes behind the inner wall 20 of the ring. This gas pressure acting on the inner wall 20 of the ring then presses the ring further outward so as to more firmly contact the cylinder wall 32.

When there is no or little gas pressure to be sealed, the ring is freed in the groove 22 and the other tension itself creates only a light pressure on the cylinder wall 32 resulting in minimal friction and wear, but when the gas pressure increases The ring acts more firmly against the cylinder wall 32 and the piston groove 22 to operate to enhance sealing and reduce leakage and provide a more efficient pollution-free engine.

The curved cross-sectional shape of the top wall 16 and bottom wall 18 of the ring 10 provides a piston ring with improved sealing and operating characteristics of the engine. By the curved shape of the upper and lower surfaces of the piston ring, a forward line contact is achieved between the wall of the groove and one of the top or bottom walls reduced inwardly of the piston ring. In particular, FIG. 4 provides a directional pressure component such that the pressure of the combustion gas is instantaneously applied to the top wall 16 and the inner wall 20 of the ring to retain the ring surface 14 in a closed relationship to the cylinder wall 32. Piston-piston ring assembly at power stroke of the engine. It can be seen that when the force acts on the ring 10, the lower wall 18 of the ring tends to slide outward along the inclined wall 28 of the groove 22. This action allows the formation of a hermetic convention between the ring face 14 and the cylinder wall 32. At the same time the lower surface 18 of the ring is at the bottom of the wall 20 of the ring as in A and at the outermost edge of the bottom wall 28 of the groove 22 as in B. It is concentrated along the bottom wall 28 and the line-to-line contacts A and B. It was found that even during the commissioning of the new ring, such a shape would improve the operating characteristics. In particular, the amount of oil consumption and blowby has been greatly reduced with the use of piston rings made according to the above description.

The technique of machining the top wall 16 and the bottom wall 18 of the ring 10 is achieved by the apparatus shown schematically in FIG. The apparatus consists of a rotating abrasive sphere 40, the outer peripheral surface of which is covered with abrasive particles. The piston ring 10 to be machined is suitably embedded in the annular retainer 42. The disk restraining plate 44 having a weave slightly smaller than the inner diameter of the retainer 42 applies the same downward pressure to the upper wall 16 of the ring 10 so that the bottom wall 18 of the ring is polished. It is used to move in contact with the spherical outer circumferential surface of the polishing sphere 40 along a straight line passing through the center 40a of the sphere 40. When the abrasive sphere 40 is rotated about its axis, the salt particles effectively form concave surfaces simultaneously in all regions of the bottom wall 18 of the embedded ring 10. Contact with the spherical polishing surface is achieved to achieve the desired concave surface. The following equation was used continuously to determine the radius of the abrasive 40 to be used for a given ring.

α = 180-90-θ = 90-θ

ψ = 180-90-α = 90-α

ψ = 90- (90-θ) = θ

ψ = θ

sin ψ = A / R or R = A / sin

Therefore, R = A / sin ψ

Where A =

θ = keystone angle

Although abrasive sphere 40 is called a sphere, the sphere is rotated around an axis passing through the other center and is intended to achieve the desired polishing action on the top or bottom walls 16, 18 of the ring 10, of the present invention. The modification (FIG. 7) forms a polishing surface with a spherical dividing surface 45a on the member 45 that rotates about the axis of the power unit 46. As shown in FIG. The main requirement of such a member 45 is that (1) the range of its working surface is such that the ring 10 is simultaneously contacted by the spherical abrasive surface 45a of all parts of the surface 16 or 18 with the embedded ring 10. ) And the relative motion of the built-in ring 10 and the spherical parting polishing surface coincides with the axis 10a (Fig. 8) of the ring 910 and the radial straight line of the spherical parting surface 45a. It is done accordingly.

7 and 8 schematically show a device for commercial production of the piston ring 10, with a number of such rings being simultaneously grounded on the rotating spherical surface 45a of the work piece 45. The power unit 46 has a housing 47 incorporating a suitable motor and drive mechanism for rotating the work member 45. In addition, a polishing slurry pump and reservoir (not shown) may be provided in the housing 47. A number of upright L-shaped support struts 50 are provided spaced apart around the housing 47, each strut acts to support an axially movable attachment 60, and within the attachment a piston ring ( 10) is built in and the shrinking surface of the ring is grounded to the spherical dividing surface in the manner shown in FIG. A conventional fluid actuated cylinder 55 is disposed on the spherical dividing work surface 45a that is suspended and rotated at the end of each support strut 50. The cylinder 55 has an output shaft 55a for supporting and axially moving the attachment hole 60, and the piston ring is exposed so that one reduced surface is engaged by the rotating spherical dividing surface 45a. 10) is fixed in the attachment hole 60. Since the mechanism for supporting the attachment 60 and moving in the axial direction is generally general, its details are not shown, but the attachment 60 and the ring 10 coincide with the axis of the embedded ring 10 and It is to be understood that it is movable to engage with the spherical dividing surface 45a along a radial straight line of the spherical dividing working surface 45a.

The abrasive particles do not necessarily have to be inserted into the spherical dividing surface of the abrasive member. Alternatively, as shown in FIG. 7, abrasive particles may be supplied to the rotating spherical divided surface of the abrasive member through a suitable pipe 70 in the form of a water base or oil base slurry.

FIG. 6 shows an embodiment of the invention similar to that shown in the embodiments of FIGS. 1-5, wherein the piston ring 10 'has only a single inwardly shrinking surface. In this particular embodiment of FIG. 6, the top wall 16 ′ is flat and perpendicular to the ring face 14 ′. The ring 10 'has an inner wall 20' parallel to the ring face 14 'and a bottom wall 18' that is inwardly reduced. The groove 22 'of the piston 24' has an internal shape similar to the cross-sectional shape of the ring 10 '. In particular, the groove 22 'has a flat top wall 26', a bottom wall 28 'reduced inwardly, and a flat rear wall 30'. As in the above embodiment, the closing action of the piston ring 10 'is enhanced in operation by the pressure of the engine gas. In the compression stroke, the pressure of the compressed gas against the upper wall 16 'of the ring 10' presses the ring downward on the lower wall 28 'of the groove 22' of the piston 24 ' Slide 10 'radially outward. This action creates a gap in the top wall 16 'of the ring 10' and allows gas pressure to move behind the inner wall 20 'and the ring 10' to expand radially outward with respect to the cylinder wall 32 '. To press more.

As in the previously described embodiment, the sealing and operating characteristics enhanced by the curved shape of the bottom wall 18 'are achieved. The line-to-line contact formed at A 'and B' between the curved bottom wall 18 'of the ring 10' and the bottom wall 28 'of the groove 22' enhances the operating characteristics.

As undesirable as the above described embodiments, another embodiment of the present invention may contemplate a piston ring having at least one inwardly contracted wall formed to have a slightly convex cross-sectional shape. The groove of the piston adapted to receive the ring is formed by the wall.

As in the embodiments described above, the sealing action of the piston ring is enhanced by the curved shape of the ring surface when it contacts each groove surface.

As described for each of the embodiments of the present invention, the novel structure of the piston ring forms a line-to-line contact between the surfaces of the piston ring and each surface of the outer circumferential groove formed in the piston. These line-to-line contacts are preferably radially separated from each other and spaced apart over most of the entire width of the upper and lower sealing surfaces of the piston ring. In addition, the force exerted on one surface of the ring by the combustion gases during operation is concentrated on the opposite surface of the ring and concentrated on the inlet groove surface along two distant line-to-line contacts as specified in FIGS. 4 and 6. It is added in the form of phosphorus.

Claims (1)

A method of simultaneously creating multiple split piston rings for a fluid pressure device with at least one inwardly reducing surface, incorporating a ring in the retainer and tangential to the inwardly reducing ring surface by having a much larger diameter than the embedded ring. Placing the built-in ring close to a spherical surface having an abrasive material in contact with it and forming an inwardly shrink ring surface, rotating the spherical surface about its center and having a curved curved surface over the entire width of the ring. A method of polishing a piston ring consisting of applying a sufficient pressure to the embedded ring along a radial path of the spherical surface such that the inwardly reducing surface of the ring is in intimate contact with the spherical surface until it is properly grounded. .

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