Hub Protection

Hub Protection – Abrasion-Resistant Rotor Hub Shields & Protectors for VSI Crushers

Superior wear resistant hub liner and rotor hub protection using basalt lined or ceramic lined technology for vertical shaft impact crushers and sand making machines

Our Hub Protection series delivers robust rotor hub protection for the central hub in Vertical Shaft Impact (VSI) crushers, sand making machines, and vertical shaft impactors. Engineered from high-strength steel with premium basalt lined, ceramic lined, or abrasion resistant composite interiors, these heavy-duty annular hub protectors and rotor hub shields withstand extreme impact, high-velocity abrasion, erosion, and corrosive conditions in mining, quarrying, aggregate processing, and crushing applications.

The donut-shaped annular design includes a thick outer steel shell for structural strength, reinforced edges, and an inner wear-resistant lining (cast basalt, alumina ceramic, or ceramic composite) offering exceptional hardness (8-9 Mohs) and smooth surface finish to minimize material adhesion, buildup, and extend service life 5-10 times longer than unprotected rotor hubs or standard hub liners.

Key Features of Hub Protection & Rotor Hub Shields

Superior Abrasion Resistance

Fused cast basalt lined or high-alumina ceramic lined for maximum wear resistant hub liner protection against sand, gravel, ore, and abrasive impacts in VSI crushers.

Corrosion & Erosion Shielding

Advanced rotor hub protection preventing damage from moisture, chemicals, high-temperature operations, and centrifugal forces in vertical shaft impact crushers.

Custom Annular Rotor Hub Design

Large-diameter ring structure precision-machined for perfect fit on VSI crusher rotors, including mounting holes for easy installation of hub protectors and shields.

Heavy-Duty Construction

Welded high-strength steel body with reinforced alloy rims for durable rotor hub shield performance and reliable abrasion resistant protection.

High Temperature Resistance

Withstands up to 350-500°C with basalt lined or ceramic lined materials, ideal for high-heat VSI crusher hub protection applications.

Low Maintenance & Cost Savings

Wear resistant hub liners and rotor hub protectors reduce replacements, minimize downtime, and lower repair costs in quarries, power plants, cement mills, and mining operations.

Hub Protection - Common Material Types

Hub Protection, are manufactured using different material compositions depending on the application, operating conditions, and performance requirements:

Composite Cast Structure

Often ceramic block inlaid roller sleeves, consisting of three layers: ductile iron (base), high-chromium cast iron (intermediate), and wear-resistant ceramic blocks (outer layer). This design balances high hardness with excellent toughness.

High-Hardness Cast Iron

Includes Ni-hard cast iron and high-chromium cast iron, achieving hardness above 58 HRC. Offers strong wear resistance but lower toughness, with potential for cracking under heavy impact.

Alloy Cast Steel

Such as ZG30Mn cast steel, optimized for improved hardness and wear resistance. Many undergo arc gouging finishing and non-destructive testing (ultrasonic, magnetic particle, dye penetrant) to ensure quality and extend service life.

Bimetal Centrifugal Casting

Outer layer uses alloy cast iron for high hardness and wear resistance, while the inner layer is gray cast iron for toughness and vibration absorption. The roller shaft is typically made of high-quality 45# carbon structural steel, assembled with interference fit for a strong, integrated structure.

Grinding Principle

Both vertical roller mills and roller presses operate based on the principle of material bed milling, ensuring efficient grinding through particle-to-particle interaction rather than direct metal contact.

Material Bed Milling Principle

During the grinding process, only a small portion of material particles directly contact the grinding components. Under applied pressure, the particles form a stable material bed. Through stress transmission and interaction between particles, the material is cracked, broken, and finely ground, resulting in high efficiency and reduced component wear.

Vertical Roller Mill Grinding Mechanism

In a vertical roller mill, the grinding components consist of rollers and a grinding disc. The grinding pressure is mainly generated by the rollers and is typically applied through a hydraulic loading system.

Material is fed onto the grinding disc from the center or side of the upper housing. As the disc rotates, a uniform material layer is formed. When the material passes between the rollers and the grinding disc, it is ground under combined extrusion and shear forces.

Roller Press Grinding Mechanism

A roller press uses two rollers of equal size as the grinding components. Material falls vertically from the top and forms a compact material bed between the rollers. Under the high extrusion force applied by the rollers, the material is compressed and ground into fine particles.

Roller presses are available in two drive configurations: double drive and single drive. The double drive roller press, where both rollers are independently driven, is the most commonly used design. In a single drive configuration, one roller is motor-driven, while the second roller is driven via a gear transmission.

Hub Protection

Design Structure

There are fundamental differences between the design structures of vertical roller mills and roller presses, which directly influence grinding efficiency, energy utilization, and product fineness.

Vertical Roller Mill: The material on the grinding disc is restricted by the air duct ring, while the material between the roller and the disc is not laterally confined. The mill typically uses two or more grinding rollers, creating a large contact area between the rollers and the grinding disc. Materials are ground repeatedly on the disc, resulting in higher energy utilization efficiency.
Roller Press: In addition to the restriction between the two rollers, side baffles are installed at both ends of the rollers, fully confining the material bed. This all-around restriction allows increased applied energy to significantly raise fine powder content and specific surface area, making the roller press superior in terms of material fineness growth.
Grinding Characteristics: The roller press features a small contact area between rollers and material, but achieves a large grinding ratio, allowing materials to be ground effectively in a single pass. In contrast, vertical mills rely on repeated grinding cycles, offering more stable operation and higher overall energy efficiency.
Performance Comparison: From the perspective of fineness increase and specific surface area, the roller press shows clear advantages. From the standpoint of energy utilization and repeated grinding, the vertical roller mill demonstrates superior performance.