Atlas Copco's Eccentric Ring main functions
Special sealing parts: In the non-circular joint surfaces of the air compressor (such as the non-circular connection points between the cylinder body and the end cover, and the connection points of irregular cavities), the special-shaped rings fill the gaps and achieve sealing by precisely matching with the contact surfaces, preventing gas or oil leakage.
Precise positioning and limit: In the special installation positions of components such as rotors, bearings, and pistons, the special-shaped rings can limit the axial or radial displacement of the components, ensuring their movement within the designed range and avoiding interference with other parts.
Buffering and shock absorption: Some elastic material special-shaped rings (such as rubber or composite materials) can absorb the vibration and shock during component operation, reducing noise and wear, and protecting the precision mating parts.
Guiding and supporting: In the non-standard trajectories of reciprocating motion components such as pistons and sliders, the special-shaped rings can provide stable guiding functions, ensuring the accuracy and smoothness of the motion.
Common types and application scenarios
Sealing special-shaped rings
Structure: The cross-section is mostly trapezoidal, wedge-shaped, or irregular shapes with lips, and the materials are usually oil-resistant rubber, polytetrafluoroethylene (PTFE), or metal-coated composite materials.
Application: Special-shaped sealing grooves on the end cover of the screw air compressor, non-circular joint surfaces between the cylinder cover and cylinder body of the piston-type air compressor, special interfaces of the oil separator, etc.
Features: The shape is completely matched with the sealing groove, achieving sealing through compression deformation, suitable for non-standard sealing surfaces.
Positioning special-shaped rings
Structure: Mostly made of metal (such as carbon steel, stainless steel), the cross-section may be L-shaped, T-shaped, or stepped, with precise dimensional tolerances.
Application: Axial positioning of the double screw rotor, gap adjustment of the bearing seat and housing, component separation in the crankcase, etc.
Features: Good rigidity, high dimensional accuracy (tolerance usually ≤ ±0.02mm), ensuring the relative position accuracy of the components.
Buffering special-shaped rings
Structure: Made of elastic materials (such as nitrile rubber, polyurethane), the cross-section may be hollow or have grooves, with a certain compression capacity.
Application: Buffering areas between valve plates and valve seats, between the piston and cylinder cover, connection points of vibration-prone components.
Features: Can absorb impact energy, reduce hard contact between metal parts, and lower noise and wear.
Guiding special-shaped rings
Structure: Made of wear-resistant materials (such as copper alloy, graphite-infiltrated cast iron), the inner hole or outer circle is of non-standard shapes (such as elliptical, ring-shaped with key slots).
Application: Reciprocating motion guiding of special-shaped pistons, support parts of eccentric shafts, etc.
Features: Low friction coefficient, good wear resistance, ensuring the smoothness of non-standard motion trajectories.
Key parameters and materials
Core parameters:
Shape dimensions: Must be completely matched with the cavity or groove of the installation position, including the dimensions of the special-shaped cross-section (such as length, width, angle, etc.).
Tolerance accuracy: Especially the dimensional tolerance and shape position tolerance of the mating surfaces (such as parallelism, perpendicularity), which directly affect the sealing or positioning effect.
Working performance: Select the appropriate material based on the requirements of the working conditions (e.g., -20℃~150℃ common, pressure resistance 0.7~2MPa, wear resistance, etc.).
Common materials:
Metal materials: Carbon steel (for positioning), stainless steel (for corrosion resistance), copper alloy (for wear-resistant guiding), suitable for high-strength and high-precision scenarios.
Non-metal materials: Oil-resistant rubber (for sealing, buffering), polytetrafluoroethylene (for low-friction sealing), composite materials (such as metal + rubber composite, combining rigidity and elasticity).
Installation points
Installation precautions:
The installation position of the special-shaped ring is unique, and it must be positioned strictly according to the assembly drawing to avoid installation errors or misalignment (some special-shaped rings have directionality).
Before installation, clean the burrs and impurities on the mating surfaces. For elastic special-shaped rings, avoid using sharp tools to grip and cause scratches or tears. For metal special-shaped rings, attention should be paid to the clearance between them. If they are too tight, it may cause assembly difficulties or component jamming; if they are too loose, it will affect the positioning accuracy.
