How to judge the quality of three-row cylindrical roller slewing rings?

What is Three-row cylindrical roller slewing rings

Three-row cylindrical roller slewing ring bearings, also known as slewing ring bearings with three-row rollers, have three housing rings that separate the upper, lower, and radial raceways, allowing the load of each row of rollers to be specified. In addition, its carrying capacity can withstand different loads at the same time. Due to the sturdy structure and large axial and radial dimensions, it is suitable for large-diameter heavy equipment such as bucket wheel excavators, wheeled cranes, ship cranes, harbor cranes, ladle turrets and heavy-duty mobile cranes.

Features of three-row cylindrical roller slewing rings

The characteristics of the three-row cylindrical roller slewing ring are mainly reflected in its unique structural design and performance advantages, and the following is a detailed description of the core features:

1. Composite bearing capacity

The three-row roller structure is adopted, and the cylindrical rollers in the middle row are vertically arranged, which mainly bear the axial load and overturning moment; The rollers on both sides are arranged in a symmetrical inclined manner, and each bears a two-way radial load. This layout allows it to withstand axial forces (Fₐ), radial forces (Fr) and overturning moments (M) at the same time, and the comprehensive load-bearing capacity is 30%-50% higher than that of single- or double-row structures.

2. High rigidity and low deformation

The rollers and raceways are designed with linear contact, the contact stress is evenly distributed, and the rigidity is 2-3 times higher than that of ball bearings. Under the rated load, the radial deformation is ≤ 0.05mm, and the axial deformation is ≤0.02mm, which is suitable for precision equipment with high precision requirements.

3. Compact and lightweight design

The three-row layout provides 15%-20% shorter axial dimensions and 10%-15% weight reduction than crossed roller bearings for the same load capacity. For example, the 1.2 m outer diameter model weighs around 300 kg, making it easy to install and transport.

4. Dynamic performance optimization

The roller adopts logarithmic convexity modification technology to reduce the edge stress concentration and improve the running stability. At 100 rpm, the vibration acceleration ≤ 1.2m/s² and the noise level ≤ 82dB, which is suitable for high-speed rotation scenarios.

5. Long life and reliability

Rated life L₁₀≥1.5×10 rpm according to ISO 281 standard life calculation. Specially designed sealing systems (e.g., Labyrinth + Lip Seal Combination) provide effective protection against dust and water intrusion, extending service life to 15-20 years in harsh environments.

How to judge the quality of three-row cylindrical roller slewing rings?

Judging the quality of three-row cylindrical roller slewing rings needs to be comprehensively evaluated from multiple dimensions such as materials, processes, structural design, testing and certification, and actual performance. Here are the key takeaways:

Materials & Processes

High-quality products are typically made of high-carbon chromium bearing steels (e.g., GCr15SiMn) or carburized steels, which require verification of carbon, chromium, and other components in the material report. After heat treatment, the raceway hardness should reach HRC58-62, and the quenching layer depth should be ≥3mm. The roundness error of the raceway is ≤0.01mm, the cylindricity error of the roller is ≤0.005mm, the Ra value of the surface roughness is ≤0.8μm, and the roller ≤ is 0.4μm to ensure that there are no scratches or burns.

Structural design

A reasonable three-row layout needs to comply with ISO standards, with the middle column carrying the axial load and the radial load sharing on both sides. The cage should be made of copper alloy or high-strength plastic, and the deformation resistance should be verified by finite element analysis. The sealing system should have a labyrinth + double lip seal combination, achieve IP67/IP69K protection, and the oil filling hole should be properly positioned, and the grease filling should occupy 30%-50% of the internal space.

Performance testing

The life test is carried out according to the ISO 281 standard, the rated life is ≥10⁶ revolution, and the actual working life needs to be more than 1.2 times the design value. Vibration acceleration ≤ 1.5m/s², noise ≤ 85dB. In terms of certification, GL certification is required in the wind power field, precision machinery needs to be accurate above P5 (radial runout≤0.02mm), and P0/P2 can be selected for ordinary working conditions.

Appearance and assembly

The surface of the raceway and rollers should be free of rust and pitting, and the cage should be free of cracks. The measurement dimensional error is controlled within ±0.05mm, and the radial clearance meets the standard (e.g. 0.15-0.25mm for the C3 group). The manual rotation should be smooth and free of jamming, and the torque fluctuation should be ≤10%.

Verification of practical applications

24 hours of operation at rated load with a temperature rise of ≤30°C and no localized overheating. The test overturning moment needs to be 1.5 times the design value without deformation. Referring to the failure rate data of similar products in wind power (20-year life) and port machinery (15 years), brands with a value of less than 0.5% are preferred.

High-quality slewing rings require material performance standards, high processing accuracy, reasonable structure, complete certification and perfect after-sales service. Third-party test reports are required for procurement, industry-certified products are preferred for key scenarios, and the liability for quality breach of contract is clarified in the contract to avoid risks.

Supplier of three-row cylindrical roller slewing rings

LTZC Bearings is a professional manufacturer of slewing bearings, slewing rings, slewing drives, and bearing components, providing high-quality and advanced solutions to customers worldwide. If you are seeking three-row cylindrical roller slewing bearings for your project, please feel free to contact us.