Bottom Shell Bushing for cone crusher Sandvik  CH780 | H7800

Engineering the Hydrodynamic Interface: Sandvik CH780 Bottom Shell Bushing Analysis

In the high-pressure environment of a Sandvik CH780 or H7800 Hydrocone, the bottom shell bushing (Item Code: 442.9360) is the primary sacrificial interface. It must maintain a consistent oil film while supporting the gyratory mass of the main shaft under cyclic loads exceeding 400 tons. Failure of this component is rarely due to simple friction; it is typically a result of material fatigue, lead segregation in the bronze matrix, or poor dimensional concentricity that disrupts the hydrodynamic lubrication wedge.

Our manufacturing process for Sandvik-compatible crusher spares moves beyond standard sand-casting. We utilize Centrifugal Casting to ensure a dense, non-porous microstructure that eliminates the “soft spots” commonly found in generic aftermarket bushings. This technical density is essential for primary and secondary crushing stations where uncrushable tramp material creates instantaneous pressure spikes.

Technical Specifications: Sandvik CH780 / H7800 Series

The following parameters represent our premium engineering standard for cone crusher parts, ensuring 100% interchangeability with OEM components.

Metallurgical Advantage: The Role of Lead (Pb)

The CH780 operates in a regime of mixed-film lubrication. During start-up and shut-down, the oil film is th
innest, and metal-to-metal contact is a constant risk. We utilize ZCuPb20Sn5 alloy because of its superior embeddability and self-lubricating properties.

• Anti-Seize Performance: The high lead content (18-23%) provides a sacrificial smear layer during emergency lubrication
  failures, protecting the expensive main shaft from galling.
• Contaminant Management: Hard particles of silica or dust that bypass the seals are safely embedded into the soft bronze matrix rather than scoring the shaft.
• Thermal Stability: Our centrifugal process ensures uniform lead distribution, preventing the “leaking” of lead that occurs in poor-quality sand castings when temperatures exceed 100°C.