Four-point contact ball bearings, also known as angular contact ball bearings, are a type of ball bearing specifically designed to handle both radial and axial (thrust) loads simultaneously. They are called “four-point” bearings because they have four points of contact with the inner and outer raceways, which allows them to accommodate various load directions and combinations of radial and axial forces. Here are some key features and characteristics of four-point contact ball bearings:

1. Four-Point Contact: Unlike typical deep groove ball bearings, which have two points of contact with the inner and outer raceways, four-point contact ball bearings have two sets of balls positioned at 45-degree angles relative to the bearing’s radial plane. This design allows them to handle axial loads in both directions.
2. High Load Capacity: Four-point contact ball bearings are known for their high load-carrying capacity, making them suitable for applications where both radial and axial loads need to be supported.
3. Axial Rigidity: These bearings provide good axial rigidity, which means they resist axial displacement under load, making them appropriate for applications where positional accuracy is essential.
4. Space-Saving Design: Four-point contact ball bearings have a relatively compact design, making them a suitable choice for applications with limited space, such as in robotics, turntables, and indexing tables.
5. Minimal Friction: These bearings exhibit relatively low friction due to the rolling contact of the balls, which results in smooth operation and reduced energy consumption.

Four-point contact ball bearings are used in a variety of applications, including:

• Slewing Rings: They are commonly used in applications like cranes, excavators, and construction equipment to enable 360-degree rotation.
• Turntables: Four-point contact bearings are used in turntables for manufacturing and assembly operations, as well as in applications like solar trackers.
• Robotics: They are utilized in robotic arms and joints, where the bearings must support both radial and axial loads.
• Machine Tools: These bearings can be found in the spindles and rotary tables of machine tools.
• Aerospace: Four-point contact ball bearings are used in some aerospace applications where they must handle combined loads and operate within strict space constraints.

The specific design and size of a four-point contact ball bearing can be tailored to meet the requirements of a particular application, considering factors like load capacity, rotational speed, and available space.