SWBTEC
Internal Gear Slewing Bearing
The selection of internal tooth slewing bearings has never been done by turning over samples and sizing down. In the actual application scenario, you must accurately rub the axial load, radial load and the most critical peak overturning moment into the dynamic cyclic load, otherwise the structural reliability is empty talk.
For excavator slewing mechanism, tower crane or turntable this heavy working conditions, I give the hard index is usually 42CrMo or 50Mn this high-strength forging material. The most easy place for technical selection to roll over is often not the raceway, but the fatigue life of the gear. The inner ring gear induction hardening is not negotiable, which is the last line of defense to prevent tooth surface pitting and early wear.
Get The Core Of Structural Reliability: Load Calculation
In the circle of heavy machinery, the inner gear slewing bearing is the “heart” of the rotating system. If you want it to run steadily, it is definitely not enough to look at the external dimensions. We often emphasize the so-called “three threats”: axial, radial and overturning forces.
Whether it is the moment generated by the tower crane in the high altitude against the strong wind, or the excavator is endlessly excavating there, the inherent advantage of the internal tooth structure is that it can absorb these composite stresses more effectively. The 42CrMo is used to ensure toughness, and 50Mn is used to ensure hardness balance. Only when the material base is thick, the bearing ring will not drop the chain when facing extreme load.
Crossing The Ridge Of Gear Fatigue: Induction Hardening
The most common failure point of the internal tooth system is often not in the raceway itself, but in the gear. At high torque transmission, the teeth are very prone to pitting and even fracture. To solve this technical bottleneck, induction hardening is a must.
Increase the hardness of the internal teeth to HRC 50-60 so that the surface can withstand the long-term wear of the drive pinion. This process directly determines the “fatigue life” of the gear. In the actual production of SWBTEC, we will strictly control the depth of the hardening layer, because once the quenching is too transparent, the teeth will become brittle, in the turntable or swing mechanism under the impact of the tooth is inevitable.
Single Row Ball Slewing Bearing
Single-row ball slewing bearings are divided into internal tooth, external tooth and toothless structure, which are suitable for a variety of transmission needs.
Double Row Ball Slewing Bearing
Double-row ball slewing bearings are specially designed for super-heavy load scenarios.
Slewing Bearing With External Gear
The external gear internal flange slewing bearing integrates the advantages of external gear transmission and internal flange mounting.
Slewing Bearing With Internal Gear
The internal tooth and external flange slewing bearing is characterized by the combination of internal tooth transmission.
Slewing Bearing Without Gear
Gearless double flange slewing bearing is light weight and compact.
Cross Roller Slewing Bearing
Single-row cross roller slewing bearing adopts roller cross layout, large contact area, can synchronously and efficiently withstand axial and radial loads and overturning moment,
Why Are Internal Teeth Often Better Than External Teeth?
Customers switch to internal gear slewing bearings for three main reasons:
- Compact structure: The teeth are integrated into the inner ring, which means that the envelope size of the whole machine can be tightened and the appearance design is more refreshing.
- With protective properties: the inner teeth are naturally wrapped by the outer ring and the machine shell. In the harsh environment of outdoor construction, this “armor” can block dust, debris and various corrosive impurities, and play a key role in protecting the pinion and meshing area.
- Torque transmission efficiency: Internal meshes usually provide a larger contact area. This directly leads to higher torque transmission efficiency and lower tooth surface pressure, and the machine runs significantly smoother.
Gouge Details: Modulus, PCD And Backlash
If you want the equipment to run steadily for years, you can’t save mathematical accuracy.
Modulus and indexing circle diameter: These two parameters determine the strength and transmission ratio of the rotating mechanism. If the modulus is selected correctly, the teeth can withstand the tangential force without shearing.
Backlash adjustment: The management of backlash is dead command. If the adjustment is too tight, the wear and tear can make you doubt your life. If the adjustment is too loose, the raceway will vibrate and the precision will disappear.
By optimizing the PCD and ensuring smooth engagement, we can minimize vibrations and thus protect the internal steel balls or rollers from eccentric wear.
Designed For Long Life
To buy a high-quality internal gear slewing bearing, you should not only take a look at the purchase price, but the subsequent downtime maintenance cost. Knock 42CrMo/50Mn forging material, keep a close eye on the induction quenching process, coupled with accurate gear parameter calculation, this is the king to keep the efficiency of the equipment.
If you need customized engineering support or high-precision internal tooth solutions, you can go to SWBTEC—we are serious about durable rotary technology.
Author: Marcus Chen
“Hi, I’m a senior mechanical engineer with over 13 years of hands-on experience in rotary system design. My expertise lies in bridging the gap between theoretical load calculations and real-world durability for heavy machinery. Throughout my career, I’ve helped hundreds of clients optimize their excavator and tower crane mechanisms by focusing on high-strength forging materials and precision gear hardening. I believe that true structural reliability isn’t found in a catalog—it’s engineered through meticulous detail.”
