What is slewing bearing -Lastest Guide to the slewing bearings

Overview of Slewing Bearings

Slewing bearings, alternatively known as turntable or rotary bearings, comprise large-sized bearings specifically engineered to concurrently support axial, radial, and moment loads. Their primary function revolves around facilitating the smooth rotation of heavy machinery and equipment.

Slewing bearings have found widespread applications across diverse industries, including construction, renewable energy, aerospace, automation, medical, marine, and heavy equipment manufacturing. Its usage spans components in crane manufacturing, excavators, wind turbines, heavy construction equipment, aerial platforms, medical imaging machinery, radar and satellite systems, tidal energy systems, and robotic arms.

Structure of Slewing Bearings

A slewing bearing’s structure includes the following components:

1. Inner ring: The inner circular part, with raceways on its inner surface and, where applicable, gear teeth.

2. Outer ring: The outer circular part, with raceways on its outer surface and, where applicable, gear teeth.

3. Rolling elements: Balls, cylindrical rollers, or a combination of both, placed between the inner and outer rings in the raceways.

4. Retainer or cage: Maintains the spacing between the rolling elements, ensuring even and controlled movement.

5. Gear teeth: Found on either the inner ring (internal gear), outer ring (external gear), or no gear at all, depending on the application requirements.

How do Slewing Bearings Work?

The core components of a slewing bearing consist of an inner ring, outer ring, rolling elements (ball or cylindrical rollers), and retainers or cages. Both inner and outer rings feature raceways and gear teeth (applicable for geared bearings) that facilitate the placement and movement of the rolling elements. As the heavy machinery rotates, relative movements between the inner and outer rings trigger motion among the rolling elements in the raceways. This mechanism, in turn, decreases the friction between components and allows for the efficient transfer of axial, radial, and moment forces.

Slewing bearings exhibit the following characteristics:

1. Ability to handle combined axial, radial, and moment loads.

2. Resistance to high and low temperatures, with some specialized types designed for extreme temperature conditions.

3. Customizable gear teeth options for different applications (internal gear, external gear, or no gear).

4. Available in various designs such as single-row or double-row ball bearings, single-, double-, or triple-row roller bearings, or combined roller-ball bearings.

5. Ability to handle high overturning moments due to their large size and configurations.

6. High-quality bearings offer a long service life and low maintenance intervals.

Working Principle of Slewing Bearings

Slewing bearings primarily function through the friction derived from components within the bearing. The rolling motion of the rolling elements imparts the necessary reduction in friction for the simultaneous transfer of axial, radial, and moment forces across the bearing. This bearing setup ensures that heavy machinery and equipment operate smoothly with minimal wear and tear.

Dimensions of Slewing Bearings

Slewing bearings come in various diameters and sizes, depending on the application and load requirements. They can range from a few inches to several meters in diameter. The exact dimensions are determined by factors such as the bearing’s design, load capacity, and rotational speed requirements. We can customize the bearings according to specific customer needs. If you need more information or requirements of slewing bearing, please feel free to contact us.

Applications of Slewing Bearings

Slewing bearings are vital for facilitating the rotation and support of heavy loads in numerous applications, such as:

1. Crane manufacturing: They ensure smooth and precise rotational movement of crane booms and load handling.

2. Excavators: Slewing bearings help excavator booms and arms perform reliable and robust rotational movements.

3. Wind turbines: They ensure that nacelles rotate precisely, enabling the wind turbine blades to adapt and face the wind direction.

4. Heavy-duty construction equipment: Slewing bearings provide rotational support in equipment like tunnel boring machines and heavy-duty drilling rigs.

5. Aerial platforms: They offer stability and rotation in boom lifts, scissor lifts, and other aerial work platforms.

6. Medical equipment: In CT and MRI scanners, slewing bearings enable accurate and smooth rotation of the scanning gantries.

7. Radar and satellite systems: They facilitate the precise and consistent rotation of radar antennae and satellite dishes for accurate tracking and data acquisition.

8. Tidal energy systems: Slewing bearings enable the rotation of underwater turbines to optimize the harvest of tidal energy.

9. Robotic arms and manufacturing systems: They maintain stability and enable precise rotation in industrial robots and other automated equipment.

Industries Using Slewing Bearings

Slewing bearings have proved indispensable across several industries, including but not limited to:

1. Construction: In cranes, excavators, drilling rigs, and tunnel boring machines.

2. Renewable energy: In wind turbines, tidal energy systems, and solar tracking systems.

3. Aerospace: In radar antennae, satellite systems, defense-related applications, and loading machinery.

4. Automation: In industrial robots, robotic arms, and other automated equipment.

5. Medical: In CT and MRI scanners, and radiotherapy machines.

6. Marine: In ship cranes, offshore equipment, and tidal energy systems.

7. Heavy equipment manufacturing: In large-scale machinery production.

How do you test a Slewing Bearing?

Multiple steps are involved in the testing of a slewing bearing:

1. Conduct a comprehensive visual inspection to identify visible damage, corrosion, cracks, or wear on the bearing components.

2. Deploy feeler gauges to measure the radial and axial clearances, ensuring they fall within acceptable limits.

3. Inspect the lubrication system and lubricate the bearing according to manufacturer guidelines.

4. Check for smooth rotation and listen to any abnormal noises emanating from the bearing, which may signal potential issues.

5. Implement non-destructive testing (NDT) methods, such as ultrasonic testing or magnetic particle inspection, to pinpoint any flaws in the bearing materials.

How to choosing the Right Slewing Bearing?

To select a suitable slewing bearing, several factors must be taken into account:

1. Load requirements: Evaluate the axial, radial, and moment loads the bearing may face during operation.

2. Operating environment: Select a bearing designed to withstand specific working conditions, such as temperature, humidity, and exposure to dust or chemicals.

3. Gear type: Choices include internal, external, or no gear, depending on application requirements.

4. Bearing size: Depending on available space and load requirements, choose an appropriate diameter.

5. Bearing type: Select from single-row or double-row ball bearings, single-, double-, or triple-row roller bearings, or a combination of roller-ball bearings, considering load capacity and rigidity requirements.

6. Material: Assess the specific requirements and operating environments to select suitable material for bearing components, such as high-strength steel or corrosion-resistant alloys.

7. Lubrication: Evaluate the lubrication requirements for the application— grease or oil lubrication— and ensure proper sealing to prolong bearing life and maintain optimal performance.

Supplier of slewing bearing

Luoyang Longda Bearing Co., Ltd.(LDB-Bearing)was established in 1999 and is located in China’s bearing production base – Luoyang, Henan. LDB Bearing has a product range from 150mm to 4000mm in diameter slew bearing and gear rings, covering the production and manufacturing of various standard and non-standard specifications of slew bearings. LDB has design and manufacturing expertise in slew bearing and slew drive across a diverse range of markets and industries.

If you need slewing bearing for your project, or want to consult some related knowledge, you are welcome to contact us at any time, our professional technology and expertise can provide you with the best solution to meet your different needs.