Crusher & Screener Drive Systems · Industrial Gearbox Engineering · Australia
Technical Specifications
Key parameters for gearboxes used in crusher and screener applications, from portable tracked jaw crushers on demolition sites to large fixed-installation cone crushers at quarries.
| Parameter | Typical Range | Notes |
|---|---|---|
| Crusher Shaft Speed | 100 – 400 RPM | Jaw crushers lower; impact crushers higher |
| Gearbox Output Torque | 1,000 – 200,000 N·m | Large quarry cone crushers at upper end |
| Service Factor | 2.5 – 4.0 | Tramp iron and rebar impact at upper end |
| Screen Exciter Speed | 600 – 1,200 RPM | Linear motion vibrating screens |
| IP / Sealing | IP65 – IP67 | Water spray and stone dust on demolition sites |
| Oil Type | Synthetic EP GL-5 | Temperature cycling from cold start to hot running |
Crusher Types and Their Gearbox Demands
Crusher gearboxes are distinguished from other industrial drives by a single dominant characteristic: the ratio between peak shock torque and steady-state running torque can exceed 10:1, driven by tramp iron, unexpected hard material, and periodic crushing cycles. The service factor must account for these peak events, not merely the average load.
Jaw Crushers: Reciprocating High-Torque Drive
A jaw crusher uses a reciprocating jaw plate to crush material against a fixed plate, with the eccentric shaft producing the jaw motion. The gearbox (typically a flywheel-connected vee-belt drive or a direct shaft coupling for smaller units) reduces motor speed to the eccentric shaft speed of 200–400 RPM and provides the torque multiplication needed to crush the hardest feed material. The flywheel stores rotational energy that is released at each crushing stroke, reducing the instantaneous torque demand on the motor and gearbox — but the torque at each jaw close is still substantially higher than the average, and the impact when tramp iron enters the chamber produces a near-instantaneous reversal shock that the gearbox must absorb without tooth fracture.
For tracked mobile jaw crushers (Metso Lokotrack, Sandvik QJ series, Terex Finlay, Powerscreen Premiertrak), the crusher drive is typically a hydraulic motor connected to the crusher shaft, with the hydraulic system providing inherent overload protection through pressure relief. For fixed and semi-mobile jaw crushers, an electric motor drives the crusher through a vee-belt sheave arrangement with the gearbox or crusher eccentric shaft driven from the sheave. Service factor 3.0–4.0 for demolition-site jaw crushers processing mixed concrete rubble with embedded rebar.
Cone Crushers: Continuous Eccentric Load
Cone crushers crush rock between a conical mantle rotating eccentrically inside a bowl liner. The eccentric motion is driven by a bevel gear and eccentric sleeve assembly, with the main shaft oscillating at 200–350 RPM. The gearbox for a cone crusher is an integrated component of the crusher design — the main drive bevel gear, eccentric shaft bearings, and lubrication system are part of the crusher housing, not a separate catalogue item. For larger quarry-scale cone crushers (Metso HP series, Sandvik CH series, Terex Cedarapids), replacement of the bevel gear set is a major maintenance event requiring specialist crusher service.
For smaller cone crushers on tracked demolition and recycling machines (Metso LT300HP, Powerscreen Maxtrak), the hydraulic motor drive system provides variable-speed operation that allows the crushing gap to be automatically adjusted to maintain constant power draw — preventing stall under variable feed hardness. The gearbox in the hydraulic motor drive system must handle the load reversals from automatic gap adjustment without backlash-induced shock that would damage the internal cone crusher components.
Vibrating Screens: Eccentric Shaft and Gearbox Synchronisation
Vibrating screens use rotating eccentric masses or eccentric shafts to generate the vibrating motion that conveys and classifies aggregate across the screen deck. For inclined vibrating screens, a single eccentric shaft driven by a direct-coupled gear motor produces circular motion. For horizontal screens requiring linear motion (for wet or fine material), two eccentric shafts must rotate at exactly the same speed in opposite directions — their combined eccentric forces cancel in the cross-deck direction and add in the conveying direction. The synchronising gearbox connecting the two eccentric shafts must maintain exact 1:1 speed ratio with zero backlash-induced timing error; any angular offset between the two shaft positions changes the vibration vector and produces off-specification screen motion that causes either material degradation or blinding of the screen apertures. Screen exciter gearboxes from OEM suppliers (Haver & Boecker, Schenck Process, Metso Screens) are precision-engineered for this requirement and are not interchangeable with standard industrial gear units.
Service Factor Philosophy for Crushing Applications
The service factor for crusher and screener gearboxes is the most conservative of any application category in this guide — and for good reason. Unlike a conveyor or pump where the peak load is bounded by the material properties, a crusher may encounter unbounded peak loads from tramp iron, unexpected hard rock inclusions, or structural steel elements in demolition rubble. The gearbox must survive these events without tooth fracture while also providing the economic service life that the machine’s capital cost demands.
Crushers processing quarried rock of known composition — limestone, basalt, granite — with the feed classified and oversize removed by primary scalping screens. The feed hardness is consistent and tramp iron is absent. Peak loads from crushing cycles are bounded by rock strength and gyratory jaw geometry. Service factor 2.5 for soft rock (limestone); 3.0 for hard rock (granite, basalt).
Crushers processing mixed demolition concrete with embedded rebar, brick, tile, and construction timber. Feed composition is unpredictable and tramp iron (wire, nails, bolt anchors) is routinely present despite magnetic separation. The peak torque event from rebar wrapping on the jaw or aggregate stalling the cone is substantially higher than in quarry applications. SF 3.0–3.5 with a verified overload protection system (hydraulic relief or torque-limited coupling) is the correct specification.
Primary and secondary crushers processing hard metalliferous ore (iron ore, gold, copper, nickel) in Australian mining operations. These are the highest-duty applications: ore hardness variability, abrasive content, and the 24/7 continuous operation cycle combine to produce the highest service factor requirement. The 20–30 year design life requirement for mine infrastructure equipment demands exceptional conservatism in gearbox specification and highly reliable condition monitoring to prevent in-campaign failures.
Applications Across Australian Construction and Mining
Sourcing Crusher and Screener Gearboxes in Australia
Crusher gearbox specifications must include: rated output torque at the service factor with peak shock load basis stated; gear ratio; bidirectional torque capability where required (cone crushers, reversing impact crushers); IP rating; housing coating for abrasive dust resistance; oil type (synthetic EP GL-5); and overload protection interface provision. For the bevel gear stages that are integral to cone crusher and jaw crusher eccentric drives, supplying accurate bevel gear load, material, and dimensional specifications to the replacement supplier confirms the mesh is correctly rated for the combined crusher torque and impact load conditions. We supply heavy-duty helical-bevel gearboxes, worm gear motors, and custom crusher gearbox solutions for demolition and quarry applications across Australia. Browse on our crusher and screener drive solutions page, or contact our engineering team for a specification within one business day.
Frequently Asked Questions
Common questions from plant managers, site engineers, and quarry operators about crusher and screener gearbox selection and maintenance.