Excéntrica | Piezas para Chancador de Cono | ATF

Eccentric Assemblies: The Heart of Gyratory Motion

The eccentric assembly is the precision mechanism that creates the characteristic gyratory crushing motion of cone crushers, converting rotational input from the drive pinion into the eccentric orbit of the main shaft and mantle that produces the compression-release crushing cycle. The eccentric throw (the offset distance between the main shaft centerline and the eccentric bore centerline, typically ranging from 10-40 mm depending on crusher model) directly determines the crushing stroke, throughput capacity, and reduction ratio of the machine. The assembly operates at rotational speeds of 200-400 RPM while supporting the full weight and crushing forces of the main shaft, mantle, and material load—total bearing loads that can exceed 200-500 kN in large machines. Eccentric housings are manufactured from cast or ductile iron with precision-machined bores, and the critical bearing surfaces are provided by centrifugally cast bronze bushings conforming to ASTM B505 or babbitt liners per ASTM B23.

Eccentric assemblies rely on precision bronze bushings that support the main shaft while allowing smooth rotation with minimal friction and wear. These bushings operate under hydrodynamic lubrication conditions where a thin oil film (typically 0.05-0.15 mm minimum thickness) separates the shaft surface from the bushing surface, preventing metal-to-metal contact. Maintaining this oil film requires correct radial clearance (typically 0.15-0.40 mm depending on shaft diameter and model), adequate oil flow, proper oil viscosity matched to operating temperature (normal sump temperature range 40-65 degrees Celsius), and clean oil free from abrasive contaminants. Worn bushings cause increased clearances that reduce oil film pressure and allow shaft wobble, generating vibration that accelerates wear throughout the crusher and ultimately leads to main shaft damage from metal-to-metal contact. ATF supplies both complete eccentric assemblies (including housing, bushings, counterweights, and gear) and individual bushing components cast from C93200 leaded tin bronze, C95400 aluminum bronze, C93700 high-lead bronze, or babbitt-lined bronze matched to the OEM specification.