{"id":6273,"date":"2026-07-08T16:51:00","date_gmt":"2026-07-08T08:51:00","guid":{"rendered":"https:\/\/www.slewbearingtec.com\/?p=6273"},"modified":"2026-07-08T17:31:39","modified_gmt":"2026-07-08T09:31:39","slug":"what-is-a-slewing-bearing-slewing-ring-applications","status":"publish","type":"post","link":"https:\/\/www.slewbearingtec.com\/fr\/what-is-a-slewing-bearing-slewing-ring-applications.html","title":{"rendered":"What Is A Slewing Bearing? Slewing Ring Applications"},"content":{"rendered":"
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Slewing bearings are by no means ordinary parts. As the 1 highly customized large-diameter rolling bearing, it can simultaneously withstand huge axial forces, radial loads and extremely exaggerated overturning moments in a single unit. From the physical structure, it is a “super joint” connecting the fixed base of the equipment and the rotating upper part. It not only comes with mounting bolt holes, but also is usually connected to the driving gear.<\/p>\n\n\n\n

It’s easy to define, but for this thing to survive in a 500-ton crane or offshore wind turbine, the water inside can be deep. The field data show a very interesting fact: 70% of the slewing bearings were scrapped early, not because the static load was wrong, but because the designer completely ignored the wear law of the equipment during dynamic swing when drawing drawings. This leads to a core question-what kind of mechanical architecture determines whether a design can run perfectly in the field or cause catastrophic downtime?<\/p>\n\n\n\n

<\/span>Core Selection Rule: C.A.R.T. Framework<\/span><\/h2>\n\n\n\n

Whether you can choose the right slewing bearing depends on how the engineer weighs the four hard indicators under the framework of C.A.R.T. Many suppliers’ selection manuals only mark the static bearing capacity of the foundation. If we only look at this, designers can easily set the parameters low in the face of complex environmental stresses. The following four dimensions to understand, in order to ensure the bearing geometry and the actual working conditions of the perfect bite.<\/p>\n\n\n\n

<\/span>Bearing capacity (Capacity)<\/span><\/h3>\n\n\n\n

Thrust and overturning moment are usually difficult at the same time, which requires a specific contact angle inside the bearing. The general load can be dealt with by a single row of four-point contact ball bearings. However, if the overturning moment of the structure exceeds the standard deformation limit, the designer must hardcore a little and directly apply three rows of cylindrical roller bearings.<\/p>\n\n\n\n

<\/span>Oscillatory arc (Arc)<\/span><\/h3>\n\n\n\n

The raceway grinds as the equipment turns. If the equipment is 360 degrees of continuous rotation, the friction and grease can be evenly distributed. However, if the equipment is only “seesaw” back and forth in a narrow dead angle of 45 degrees, the local rolling elements will be “exhausted” because of stress concentration “.<\/p>\n\n\n\n

<\/span>Rigidity (Rigidity)<\/span><\/h3>\n\n\n\n

If the mounting base itself is deformed under soft stress, the rigidity of the slewing bearing is a joke. The mounting surface attached to the bearing must be precisely machined to ensure absolute flatness, otherwise once the weight is lifted, the bearing will be pulled into an oval shape.<\/p>\n\n\n\n

<\/span>Torque<\/span><\/h3>\n\n\n\n

The size of the internal pre-tightening force directly determines how much effort you want to make the car part turn. In the field of precision robots, in order to completely eliminate the gap, designers will deliberately use negative clearance-of course, the price is soaring friction, and the rotary drive must provide more starting torque to move.<\/p>\n\n\n\n

C.A.R.T. Metrics Comparison Table<\/p>\n\n\n\n

Metric<\/td>Single-row Ball (Four-Point Contact)<\/td>Crossed Roller<\/td>Triple-row Roller<\/td><\/tr>
C – Capacity<\/strong><\/td><\/td><\/td><\/td><\/tr>
Axial Load Capacity<\/em><\/td>Moderate<\/td>High<\/td>Very High (Highest)<\/td><\/tr>
Radial Load Capacity<\/em><\/td>Moderate<\/td>High<\/td>Very High (Highest)<\/td><\/tr>
Moment Load Capacity<\/em><\/td>Moderate<\/td>High<\/td>Exceptionally High<\/td><\/tr>
Envelope Efficiency<\/em><\/td>High (Good capacity for its size)<\/td>Very High (High capacity in compact space)<\/td>Moderate (Requires larger envelope)<\/td><\/tr>
A – Accuracy<\/strong><\/td><\/td><\/td><\/td><\/tr>
Rotational Accuracy (Runout)<\/em><\/td>Moderate<\/td>High to Very High<\/td>Moderate to High<\/td><\/tr>
Backlash \/ Play<\/em><\/td>Standard clearance; difficult to preload heavily<\/td>Can be preloaded for zero clearance \/ backlash<\/td>Generally has slight clearance; less ideal for high-precision positioning<\/td><\/tr>
R – Rigidity<\/strong><\/td><\/td><\/td><\/td><\/tr>
Radial\/Axial Stiffness<\/em><\/td>Moderate (Point contact leads to more deflection)<\/td>High (Line contact increases stiffness)<\/td>Very High (Multiple roller rows minimize deflection)<\/td><\/tr>
Moment Rigidity<\/em><\/td>Moderate<\/td>High<\/td>Exceptionally High<\/td><\/tr>
T – Torque<\/strong><\/td><\/td><\/td><\/td><\/tr>
Frictional Torque<\/em><\/td>Low and relatively consistent<\/td>Moderate to High (Increases with preload)<\/td>High (Due to multiple rollers and seals)<\/td><\/tr>
Torque Sensitivity to Mounting<\/em><\/td>Low to Moderate (More forgiving of structure flatness)<\/td>High (Requires very flat mounting surfaces to avoid binding)<\/td>Moderate to High<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

<\/span>“Exclusive” Architecture Configuration For Top Industries<\/span><\/h2>\n\n\n\n

Equipment manufacturers will plug different internal structures into the slewing bearing according to the requirements of different industries. Whether to use balls, cross rollers, or multi-row rollers that separate the force depends on the specific application scenario.<\/p>\n\n\n\n

<\/span>Wind power industry: yaw and pitch systems<\/span><\/h3>\n\n\n\n

The fan blades will produce continuous small movements when pitching, which are extremely unfriendly to standard bearing raceways. The yaw slewing bearing installed on the top of the tower is required to simultaneously resist the terrifying wind shear and the extremely exaggerated overturning moment of the engine room. In order to cope with the harsh weather at sea, engineers usually hit the heavy cost here, using double-row ball bearings or cylindrical roller variants with heavy seals.<\/p>\n\n\n\n

<\/span>Heavy machinery: Excavators and tower crane<\/span><\/h3>\n\n\n\n

Excavators particularly rely on slewing bearings with internal teeth, mainly to hide the drive pinion inside, from the erosion of the site sediment. Due to the extreme “seesaw effect” caused by the huge counterweight and the extended boom, engineers generally use three-row roller slewing bearings. This structure distributes thrust, radial force and overturning force to a 3 independent raceway, ensuring that the chassis of the excavator is still stable when the excavator is fully loaded and the arm is fully open.<\/p>\n\n\n\n

\"an<\/figure>\n\n\n\n

<\/span>Precision Robotics and Medical Equipment<\/span><\/h3>\n\n\n\n

Surgical imaging equipment is extremely demanding: rotational runout must be close to zero and run absolutely quietly. In the face of this demand, the cross roller slewing bearing has become the choice. The internal cylindrical rollers are arranged alternately at 90 degrees, which can handle high torque loads in an extremely compact cross-section, which not only ensures the high precision of medical equipment, but also reduces the overall weight.<\/p>\n\n\n\n

<\/span>Easiest Pit To Step On: “False Indentation” And Fretting Wear<\/span><\/h2>\n\n\n\n

In the working condition of short arc swing back and forth, the early failure caused by inadequate lubrication is definitely the number one culprit for the scrapping of heavy equipment slewing bearings.<\/p>\n\n\n\n

Many designers will take it for granted according to the assumption that the equipment will turn 360 degrees continuously. Continuous rotation can indeed drag the grease evenly across the entire bearing area and protect the rolling elements; but in reality, like cranes and material handlers, they often only knock back and forth in a narrow angle of 60 degrees. This repeated fretting with heavy loads will force out the grease on the contact surface. Without oil, steel and steel are dry ground directly, and finally deep pits are smashed on the raceway-what the industry calls “false indentation” (False Brinelling).<\/p>\n\n\n\n

How to break this bureau? The engineer’s current play is: standard automatic multi-point progressive lubrication system. When the equipment is in operation, it is specially selected to carry the sector with the most severe overturning torque and pump fresh grease into it.<\/p>\n\n\n\n