DE202010018209U1 - Compression piston ring - Google Patents

Abstract

Compression piston ring for an internal combustion engine or a compression machine, comprising a tread (10), an upper (8) and a lower ring flank (13) and an inner peripheral surface (11), the surfaces of the ring flanks (8, 13) being provided with different roughnesses the ring flank (8) facing the combustion or compression chamber (B) has a greater roughness (Rz according to standard DIN EN ISO 4287) than the ring flank (13) facing the crankcase (K), which is designed so that it is oriented in such a way that channels (15) run from the tread (10) to the inner circumferential surface (11), the ring flank (13) facing the crankcase (K) being designed in accordance with the usual roughness in the range between Rz 0.8 and Rz 4.

Description

The innovation relates to a compression piston ring for an internal combustion engine.

Compression piston rings have the task of sealing the combustion chamber against the crankcase with minimal friction and to limit oil consumption. This function is achieved essentially by the piston ring tangential force and by the contact force of the gas pressure on the ring upper edge and the inner ring area. As a result, a good contact pressure is applied to the lower piston groove flank and to the cylinder wall.

In order to have a sufficient cross section between the Kolbennutoberflanke and the piston ring upper edge for this gas pressure, a Mindestnutspiel is necessary. The piston ring tangential force counteracts the increasing gas differential pressure between ring raceway and groove base. This gas differential pressure is dependent on the groove play. Although a large groove play improves the pressure build-up and pressure reduction in the groove bottom, but leads to increased wear on the Kolbennutflanken and ring flanks by the increased system change and deteriorates additionally the oil consumption and the blow-by behavior of the engine. A small groove play, on the other hand, impedes the pressure build-up in the groove base and can lead to collapse of the piston ring into the groove, which in turn can have a negative influence on the blow-by behavior and the oil consumption. In addition, a too small Nutspiel lead to jamming of the piston ring in the piston groove.

The US 2,186,020 describes a piston ring specifiable geometric contour, which is used as a compression piston ring. The combustion chamber facing the annular flank is provided with radially extending grooves extending from the tread to the inner peripheral surface of the piston ring, and thus serve the gas pressure build-up between the groove bottom and the inner peripheral surface of the piston ring. On the combustion chamber facing the annular flank several grooves predeterminable circumferential length and depth are introduced. Due to this configuration of the combustion chamber facing the annular flank of the piston ring whose supporting share is reduced. In addition, a significant weakening of the piston ring cross section is brought about.

The innovation is based on the object to further develop the state of the art to the effect that the disadvantages mentioned are eliminated and beyond very quickly a gas pressure build-up / gas pressure reduction can take place in the groove bottom even with the smallest Kolbennutspiel.

This object is achieved by a compression piston ring for an internal combustion or a compacting machine, comprising a running surface, an upper and a lower annular edge and an inner peripheral surface, wherein the surfaces of the annular edges are provided with different roughnesses, the combustion or compression space facing annular edge greater roughness (Rz according to Standard DIN EN ISO 4287 ) as the crankcase facing the annular flank, which is designed so oriented that channels extend from the tread to the inner peripheral surface wherein the crankcase facing ring flank is formed according to a usual roughness in the range between Rz 0.8 and Rz.

Advantageous developments of the subject invention can be found in the dependent claims.

The renewal compression piston ring has on the combustion chamber facing the upper surface of a structured surface geometry, which allows gas transport radially to the piston ring. This gas-permeable piston ring upper edge makes it possible for the gas pressure from the combustion chamber (compression chamber) to propagate very rapidly to the annular top surface and the groove base in all work cycles of a two- or four-stroke engine and a compression machine. Rapid pressure build-up on the ring surface and groove bottom is necessary for good edge and tread sealing. This design feature also supports backflow of the gas from the bottom of the groove to the combustion chamber and can thus reduce the blow-by behavior of the engine. In addition, the tangential force of the piston ring can be reduced, since then only a short-term and low pressure difference between ring raceway and groove bottom can be adjusted. A reduction in the piston ring tangential force also reduces the friction loss of the engine. By this measure can be reduced to the risk of a fixing ring in the groove, since despite the slightest Nutspiel the gas pressure can propagate into the groove base and the piston ring to the mating surface, for example, a cylindrical surface pressed. This surface should be designed radially so that the ring surface is a plateau with approx. 50% bearing capacity at the surface and approx. 80% at a depth of approx. 0.02 mm.

Similar to the prior art according to US 2,186,020 , This surface structure can also be introduced into the Kolbennutoberflanke.

The desired surface structure, for example, by a concentric over the ring circumference grinding process with a radial Cutting depth of about 0.03 mm and then fine sanding be generated.

Compared to the prior art, a compression piston ring is thus provided, which has an optimum support share on the surface of the flank facing the combustion chamber.

The object of the invention is illustrated by means of an embodiment in the drawing and will be described as follows. Show it:

1 Schematic diagram of a piston receiving a plurality of piston rings;

2 Representation of the piston ring in the first and second groove of the piston according to 1 ,

1 shows a schematic diagram of a piston 1 for an internal combustion or compaction machine (not shown).

In this example, the piston should 1 three grooves 2 . 3 . 4 exhibit. The grooves 2 . 3 serve to accommodate compression piston rings 5 . 6 while the groove 4 an oil scraper ring 7 receives. The combustion chamber is indicated by the letter B and the crankcase by the letter K. Arrows indicate the gas flow from the combustion chamber B in the direction of the compression piston rings 5 . 6 indicated. Through the gas-permeable piston ring upper edge 8th It is now possible that in all work cycles of a two- or four-stroke engine and in a compacting machine, the gas pressure from the combustion chamber B from very quickly on the ring upper edge even with the smallest Kolbennutspiel 8th and the groove bottom 9 can reproduce.

2 shows the example in the groove 1 introduced compression piston ring 5 in different views. Visible is the tread 10 , the inner peripheral surface 11 , the push 12 and the piston ring upper edge 8th and the piston ring lower edge 13 , Only indicated is the surface structure 14 the combustion chamber B facing the piston ring flank 8th , The combustion chamber B ( 1 ) facing flank 8th has a higher roughness Rz than the crankcase K facing edge 13 , The roughness Rz is in accordance with the applicable Standard DIN EN ISO 4287 on the flank 8th adjust. The roughness of the crankcase K facing flank 18 should have a roughness in the range between Rz 0.8 and Rz 4 in this example. Recognizable are channels 15 on the piston ring flank 8th , which have a predetermined width and depth and starting from the tread 10 towards the inner peripheral surface 11 of the piston ring 5 extend and thus a gas-permeable piston ring upper edge 8th form. In the combustion chamber B facing the piston ring flank 8th For example, the surface structure becomes a concentric grinding process 14 produced, with a radial depth of cut of about 0.03 mm is provided.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2186020 [0004, 0009]

Cited non-patent literature

• Standard DIN EN ISO 4287 [0006]
• Standard DIN EN ISO 4287 [0017]

Claims (7)

Compression piston ring for an internal combustion or compacting machine, including a tread ( 10 ), an upper ( 8th ) and a lower ring flank ( 13 ) and an inner peripheral surface ( 11 ), wherein the surfaces of the ring flanks ( 8th . 13 ) are provided with different roughnesses, the combustion or compression space (B) facing the ring flank ( 8th ) a greater roughness (Rz according to standard DIN EN ISO 4287) than the crankcase (K) facing the ring flank ( 13 ), which is designed in such a direction-oriented manner that channels ( 15 ) from the tread ( 10 ) to the inner peripheral surface ( 11 ) run whereby the crankcase (K) facing the ring flank ( 13 ) is formed according to a usual roughness in the range between Rz 0.8 and Rz 4. Compression piston ring according to claim 1, characterized in that the channels ( 15 ), starting from the tread ( 10 ), to the inner peripheral surface, ( 11 ) run straight. Compression piston ring according to claim 1, characterized in that the channels ( 15 ), starting from the tread ( 10 ) to the inner peripheral surface, ( 11 ) run to a predetermined curve profile. Compression piston ring according to one of claims 1 to 3, characterized in that the surface structure ( 14 ) of the combustion chamber (B) facing the ring flank ( 8th ) is produced by grinding, broaching, cloth or by another manufacturing method. Compression piston ring according to one of claims 1 to 4, characterized in that the depth of the channels ( 15 ) is between 0.01 and 0.05 mm. Compression piston ring according to one of claims 1 to 5, characterized in that the channels ( 15 ) have a width between 0.1 and 0.5 mm. Compression piston ring according to one of claims 1 to 6, characterized in that following the introduction of the channels ( 15 ) in the ring flank ( 8th ) the combustion chamber (B) facing the ring flank ( 8th ) is finished by fine grinding, by lapping or by smoothing.

Images