Manufacturer of piston rings, oil scraper rings, sealing rings

The appointment, conditions of operation, design features.

Piston ring, for all its seeming simplicity is one of the most important parts in mechanical engineering. As for the operation of the internal combustion engine, a piston compressor or turbocharger is required reliable sealing of the working chamber from the blow-by, high-quality to eat and the withdrawal of lubricant from the working zone. For this purpose, piston rings.

Their purpose piston rings are divided into compression (figure 1) and oil (figure 2). Compression rings can be equipped with additional groove – scraper, which serves to enhance the effect of the removal of oil from the cylinder walls.

Types, basic parameters and dimensions of the piston rings is regulated by GOST 621-87 "piston Rings of internal combustion engines. General technical conditions"

Piston rings differ in design of locks (figure 3).

Material and methods for the production of blanks.

The plant manufactures piston rings piston and seal rings made of special alloyed cast iron of various grades:

- Cast iron pug (similar СЧ36) – cast iron pearlitic class with evenly distributed plate-vermicular graphite with high mechanical properties, good elasticity and abrasion resistance. From this material we produce piston rings for compressors, seal rings for transmissions and hydraulic machines.

- Cast ductile iron (similar to ВЧ80-ВЧ100) is a high – quality high-strength cast iron with spherical graphite pearlitic class with close to the steels ductility, high elasticity and abrasion resistance. Of such material produced piston rings for locomotive and marine engines, turbochargers, two-stroke engines. Due to the spherical graphite, uniformly distributed throughout the cross section of rings, this iron is not inferior in wear resistance to chrome-plated counterparts.

The quality of the castings because of the difficult working conditions of the piston rings must meet higher requirements than most other castings of similar brands. Castings get a new unique method of casting freezing, thereby to achieve a very high material quality of the piston rings.

Due to the high speed of crystallization and unidirectional heat sink (figure 4), in the casting, it produces highly dispersed, oriented perpendicular to the surface of the heat sink microstructure (figure 5). Thus, in the finished piston ring, dendrites – crystals (figure 6 a, b), is most strongly opposed to wear and tear are located in a plane perpendicular to the friction surface (figure 6). This structure is typical of ingot casting only for freezing and optimally to withstand the wear and tear of parts such as bodies of rotation. As a result, the wear resistance of piston rings obtained by casting freezing at least 30-40% higher than the rings produced by other casting methods.

Figure 4. The principle of formation of casting when casting freezing

Figure 5. The General scheme of the areas and zones in the solidifying ingot when casting freezing

Figure 6. Dendrites – schematically; photo; piston ring

Manufacture of piston rings.

Despite its apparent simplicity, the technology of manufacturing piston rings is one of the greatest challenges of engineering. High demands on dimensional accuracy, form and mutual location of surfaces of piston rings are designed to provide excellent adhesion of the ring to the cylinder wall and the installation groove of the piston with the required minimum clearances. Additional complexity for Metalworking is Prestcott ring design.

Dimensional accuracy on the major surface is maintained at 7 degree. The roughness of the outer cylindrical surface of the ring Ra is 2.5 μm. This roughness ensures good adjustment to the mirror cylinder.

The roughness of the end surfaces of the ring Ra = 0.63 µm. This roughness ensures easy movement of the rings in the grooves of the piston, and also prevents wear of the end faces of the rings and the walls of the grooves. High precision the distance between the ends improves the condition of the piston seal.

Manufacturer of piston rings produced on the new turning centers MAZAK, DMG, Victor, etc., using the tool of leading world manufacturers. This provide a high precision machining and 100% fit the rings to the cylinder.

The most important indicator for piston rings is the force with which the ring presses against the cylinder. This value is calculated for each type of rings, and depends on many factors: the material of the rings, the material of the sleeve, working conditions, etc. thus the elasticity of the rings must be sufficient to ensure sealing of the working chamber, removing and discharging the lubricant, but it does not cause excessive wear of rings and liners.