SWBTEC
¿Cuál es el par de un rodamiento giratorio?
In the actual mechanical design, you must not regard it as a rigid static value, it is actually a dynamic combination of “starting torque” and “running torque. The starting torque is usually much greater than the operating torque to maintain continuous movement. The generation of this kind of resistance is essentially the result of the axial load, radial load and overturning moment that squeeze the raceway together, resulting in friction between the rolling body and the raceway. In addition to these external loads, the total torque is strongly influenced by the internal friction coefficient, the seal-induced drag and the grease viscosity.
Starting Torque Vs Running Torque
Starting torque, the industry is often called “torque”. The reason why its value is significantly higher is that the system must first handle the static friction and the “adsorption effect” of the lubricant due to sedentary “. If an engineer only looks at the running torque, the drive motor is likely to be weak at the moment of starting, directly causing the system to jam or the motor to overload. If you want the equipment to smoothly transition from static to normal speed rotation, you must have a deep understanding of these dynamic forces, otherwise the life of the driving parts is not guaranteed at all.
Interaction Of External Loads
The number one driver of the slewing bearing torque is the load distribution it carries:
- Carga axial: This vertical pressure will directly press the ball or roller to the raceway, increasing the contact area, and the friction will naturally go up.
- Carga radial: This horizontal thrust will squeeze the bearing ring to the side, which will change the contact angle of the rolling body, thereby increasing the additional rotation resistance.
- Momento de vuelco: This is usually the most troublesome factor. It acts like a lever to make the internal force of the raceway extremely uneven.
When these three forces are mixed together, they form a very complex friction model. When working on heavy crane or aerial platform projects, the overturning moment will locally generate extremely high pressure areas, and the torque required in this case will be several times higher than the simple balanced load condition.
Coronas de giro de bolas de una hilera
Los rodamientos giratorios de bolas de una hilera se dividen en estructura de diente interno, diente externo y sin dientes, que son adecuados para una variedad de necesidades de transmisión.
Coronas de giro de bolas de doble hilera
Los rodamientos giratorios de bolas de doble hilera están especialmente diseñados para situaciones de cargas superpesadas.
Coronas de giro con engranaje exterior
El rodamiento giratorio con engranaje externo y brida interna integra las ventajas de la transmisión con engranaje externo y el montaje con brida interna.
Coronas de giro con engranaje interior
El rodamiento giratorio de diente interno y brida externa se caracteriza por la combinación de transmisión de diente interno.
Coronas de giro sin engranaje
El rodamiento giratorio de brida doble sin engranajes es ligero y compacto.
Coronas de giro de rodillos cruzados
El rodamiento giratorio de rodillos cruzados de una hilera adopta una disposición cruzada de rodillos, gran área de contacto, puede soportar de forma sincrónica y eficiente las cargas axiales y radiales y el momento de vuelco,
Internal Factors
In addition to the heavy pressure on the outside, some “invisible” components inside the bearing also play an important role in defining the torque.
- Seal resistance: High-quality seals are indeed essential to protect the raceway from contamination, but they also cause friction when they are close to the rotating ring. This “drag feeling” is a constant basic resistance, which must not be missed in the calculation, especially in precision bearings with small external load, the proportion of sealing resistance will be particularly prominent.
- Lubricación: The viscosity of the grease inside the bearing is like a fluid resistance. In a cold environment, the grease thickens and the starting torque will be much greater than in warm conditions. Grease selection is actually a balance between “protecting the metal surface” and “reducing excess torque”, which is quite a test of craftsmanship.
Impact On The Selection And Efficiency Of The Drive System
Whether the torque is accurate or not is directly related to the selection of other components of the whole rotary system. It directly determines the specifications of the drive motor and the speed ratio of the reducer. Deeply speaking, the torque value also determines the force level of the pinion and the bearing ring gear itself. If the torque is estimated to be small, the tooth surface may wear out prematurely or even collapse directly. On the other hand, if the estimation is too conservative, the motor will be stupid, which will not only cost money but also take up space, and the efficiency of the whole machine will be ridiculously low.
For those engineers who want to refine the design scheme, it is a prerequisite to find a bearing with transparent torque parameters and reliable data. Manufacturers like Slew Bearing Tec provide technical support and manufacturing technology to ensure that the measured performance of the bearing matches your theoretical calculation, so that cranes, solar trackers or industrial machinery can move smoothly.
Autor: Robert Chen
I have guided the design and implementation of slewing bearings for everything from massive harbor cranes to high-precision solar trackers. My focus is on helping fellow engineers bridge the gap between theoretical calculations and real-world performance. I believe that understanding the nuance of torque is the key to building more efficient, reliable, and cost-effective machinery.
