Structured Manufacturing Data (2026)

Slewing Unit

Based on aggregated insights from structured factory profiles within the CNFX directory, the standard Slewing Unit used in the Machinery and Equipment Manufacturing sector typically supports operational capacities ranging from standard industrial configurations to heavy-duty production requirements.

Technical Definition & Core Assembly

A canonical Slewing Unit is characterized by the integration of Slewing Bearing and Slewing Motor. In industrial production environments, manufacturers listed on CNFX commonly emphasize High-strength alloy steel construction to support stable, high-cycle operation across diverse manufacturing scenarios.

A mechanical assembly that enables the rotation of the tower crane's upper structure (jib and counter-jib) relative to the stationary tower.

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Product Specifications

Technical details and manufacturing context for Slewing Unit

Definition
The slewing unit is a critical component of a tower crane that facilitates the horizontal rotation of the crane's upper works, including the jib (working arm) and counter-jib (counterweight arm). It is mounted between the stationary tower (mast) and the rotating superstructure (slewing platform), allowing the crane to swing loads through a full 360-degree circle. This precise rotational movement is essential for accurate load positioning on construction sites.
Working Principle
The unit typically consists of a large-diameter slewing bearing (ball or roller bearing) that supports the rotating superstructure. A slewing drive mechanism, often comprising an electric motor, gear reducer (planetary or worm gear), and pinion, engages with a gear ring attached to the bearing. When activated, the motor drives the pinion, which rotates the entire upper structure around the fixed tower. Modern units often incorporate frequency-controlled drives for smooth, controlled acceleration and deceleration.
Common Materials
High-strength alloy steel, Case-hardened bearing steel, Cast steel
Technical Parameters
  • Slewing torque capacity, indicating the rotational force the unit can transmit to overcome load inertia and friction. (Nm) Customizable
Components / BOM
  • Slewing Bearing
    Supports the rotating superstructure and facilitates smooth rotation with minimal friction.
    Material: Case-hardened bearing steel
  • Slewing Motor
    Provides the primary rotational power to drive the slewing mechanism.
    Material: Copper windings, steel housing
  • Planetary Gear Reducer
    Reduces the high-speed, low-torque output of the motor to low-speed, high-torque output suitable for rotating the crane.
    Material: Alloy steel gears, cast iron housing
  • Pinion Gear Part
    The final drive gear that meshes with the bearing's internal or external gear ring to transmit rotation.
    Material: Hardened alloy steel

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Slewing Unit.

Slewing Assembly Slewing Gear tower crane slewing unit assembly heavy-duty slewing bearing for cranes planetary gear reducer slewing motor case-hardened steel slewing pinion gear industrial machinery slewing rotation system

Applied To / Applications

This component is essential for the following industrial systems and equipment:

Tower Crane
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Industrial Ecosystem & Supply Chain Structure

Complementary Systems
Downstream Applications
Specialized Tooling

Application Fit & Sizing Matrix

Operational Limits
pressure: Not applicable (mechanical assembly)
other spec: Max torque: 50-500 kNm (depending on model), Max axial load: 100-1000 kN, Max radial load: 50-500 kN
temperature: -20°C to +50°C
Media Compatibility
✓ Industrial lubricants (grease/oil) ✓ Dry air environments ✓ Clean mechanical operation
Unsuitable: Corrosive chemical exposure (acids, salts)
Sizing Data Required
  • Maximum operating torque (kNm)
  • Maximum axial load capacity (kN)
  • Required rotation speed (RPM)

Reliability & Engineering Risk Analysis

Failure Mode & Root Cause
Bearing fatigue and spalling
Cause: Cyclic loading from rotational forces exceeding design limits, improper lubrication leading to metal-to-metal contact, or contamination ingress causing abrasive wear.
Gear tooth pitting and scoring
Cause: Inadequate lubrication film thickness, misalignment of gear meshing surfaces, or overloading beyond rated torque capacity causing surface fatigue.
Maintenance Indicators
  • Abnormal grinding or metallic knocking sounds during rotation
  • Visible oil leaks around seals or excessive vibration during operation
Engineering Tips
  • Implement condition-based lubrication with oil analysis to monitor contamination levels and additive depletion, ensuring optimal viscosity and cleanliness.
  • Install vibration monitoring sensors with trend analysis to detect early-stage bearing and gear degradation before catastrophic failure occurs.

Compliance & Manufacturing Standards

Reference Standards
ISO 12100:2010 - Safety of machinery ANSI/AGMA 2000-A88 - Gear Classification and Inspection Handbook DIN 3962 - Tolerances for cylindrical gear teeth
Manufacturing Precision
  • Bore diameter: +/-0.015mm
  • Mounting surface flatness: 0.05mm
Quality Inspection
  • Hardness testing (Rockwell C scale)
  • Gear tooth profile inspection via coordinate measuring machine

Factories Producing Slewing Unit

Manufacturer profiles with relevant production capability in China

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Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

Technical documentation
4/5
Manufacturing capability
4/5
Inspection readiness
5/5
Supplier transparency
3/5

These scores are example evaluation dimensions, not real customer ratings, country-specific buyer feedback, or live inquiry activity.

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Frequently Asked Questions

What materials are used in manufacturing slewing units for maximum durability?

Our slewing units are constructed from high-strength alloy steel, case-hardened bearing steel, and cast steel components to withstand extreme loads and ensure long service life in demanding crane operations.

How does the planetary gear reducer improve slewing unit performance?

The planetary gear reducer provides high torque transmission with compact design, ensuring smooth rotational control, reduced backlash, and efficient power transfer from the slewing motor to the pinion gear.

What maintenance is required for slewing bearings in tower crane applications?

Regular lubrication inspection, seal integrity checks, and monitoring for abnormal noise or vibration are essential. Most slewing bearings require lubrication every 250-500 operating hours depending on load conditions.

Can I contact factories directly on CNFX?

CNFX is an open directory, not a transaction platform. Each factory profile provides direct contact information and production details to help you initiate direct inquiries with Chinese suppliers.

Data basis: CNFX manufacturer profiles, technical classification, publicly available product information, and ongoing plausibility checks for Machinery and Equipment Manufacturing.

Data Basis

CNFX manufacturer profiles, technical classification, publicly available product information, and ongoing plausibility checks.

Preliminary Technical Classification
This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

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