Double four-point ball slewing bearings with External Gear for New Holland W190 log loaders / feller heads

Forestry feller-buncher  are used in many fields of forestry, whether as mobile machines in the forest or as stationary units in sawmills. Working in the forest presents a special set of challenges. These include uneven ground, working on steep slopes and in the smallest of spaces. Thus, high-quality flexible units with mobile pivot arms designed for heavy loads are in demand. Our products fulfill these demands reliably and with high economic efficiency as construction and connection components.

The components of forestry equipment must be sturdy and durable. They work in rugged environments and need to be designed and maintained to withstand harsh weather conditions. This means that their rotary bearings must be able to work together with the high speed of the deaerator at low temperatures. The slewing bearing used by log loaders / feller heads is a Double four-point ball slewing bearings , and the teeth are quenched. The motor or reducer drives the pinion to rotate, and the pinion drives the slewing bearing to rotate, so that the upper mechanism connected to it rotates accordingly.

Special heat treatment design is carried out according to the different needs of specific industries for gears, mainly including induction single-tooth quenching and induction-type integral tooth quenching. Single tooth quenching is divided into tooth surface quenching and tooth surface and root quenching. After quenching, tempering treatment is carried out to make the surface hardness and the depth of the hardened layer meet the design standards. The most advantageous process is the special process of integral tooth quenching, which can improve the transmission efficiency and increase the wear resistance and impact resistance of the tooth surface, so as to meet the needs of customers.

Raceway heat treatment and tooth heat treatment are the biggest advantages of  longwei transmission slewing bearing co.,ltd.

Tooth heat treatment is an important process in the processing of slewing bearings, and the application of some products requires relatively high hardness of the tooth surface. Through high-frequency induction hardening, the bearing tooth surface can be hardened, effectively increasing the strength and service life of the product. We can perform single tooth quenching or overall quenching according to the modulus and product design requirements.

When continuous induction heating quenching is performed on the raceways of the slewing ring gear and the rolling ring, attention should be paid to the connection between the starting point and the end point of the slewing ring quenching. If the slewing bearing quenching belt overlaps, cracks are likely to occur. For this reason, a certain distance should be maintained at the head-to-tail quenching connection of the slewing ring.

raceway quenching

Slewing bearing its gear precision grade should be between 7 to 11, which determines the smoothness of the slewing bearing drive, load distribution uniformity and transmission accuracy. The higher the slewing bearing gear precision, the more intensive the mesh tooth surface contact spots, so that the noise value is reduced, the smoothness of operation improved. 

The contact and bending strength of gears under ultimate and fatigue loads were calculated and verified according to ISO6336-1:2006, ISO6336-2:2006 and ISO6336-3:2006 respectively. Sf is 1.48 and the gear mesh clearance is adjusted for the highest point of radial run out of the slewing bearing  gear pitch circle. The minimum tooth clearance is typically 0.03 to 0.04x modulus, and the gear mesh clearance of the pinion gears on the entire circumference needs to be re-checked after final fastening of the slewing bearing . 

If the weld quality is not up to standard, the weld defect needs to be reworked and rewelded. In the repair welding repair will not only produce new welding stress and the flatness of the machined mounting surface will also have a great impact, at the same time the welding current generated in the slewing bearing through the internal rolling body and slewing ring raceway will also cause some damage. In addition, assembly errors in manufacturing assembly, field installation of the pin threading and bolt preload can also produce abnormal noise or chatter if the requirements are not met.


slewing ring main forms are external and internal type, the large and small gears mesh poorly, sometimes tight, sometimes loose, in the slewing ring tooth run out maximum position meshing too tight produce noise. So the manufacturing process is critical. Slewing bearing just left the factory in idling will issue a steel ball rolling uniform sound, which is normal. Such as in the uniform normal ringing accompanied by another abnormally large ringing is abnormal. There are many reasons for the failure.

Gear meshing image

Technical parameters required for slewing bearing selection as below:
1).Slewing bearing load (Includes axial load, radial load and tilting moment)  
2). Percentage of each load and its occupation time
3). Speed or number of revolutions of the slewing bearing under each load
4).Circumferential force acting on the gear
5).Dimensions of the slewing bearing
6). Other operating conditions.

The material, compressive property, abrasive resistance and hardness of balls will affect the load condition and service life of slewing bearing. Longwei  slewing bearing Co., Ltd purchase balls from suppliers with high quality, and we will conduct test for the compressive property, abrasive resistance and hardness to eurens the quality of balls will meet the requirement.

About Longwei

Provide you with customized industry solutions

longwei factory

More than ten years of production experience, strict quality control can be the guarantee of the best solution in the industry.
China’s leading supplier of slewing bearings, its products have passed ISO 9001 and CAPE certification, and has a number of product patents.

The flexibility of our dialogue and approach with our clients is combined with responsive design and development innovation to ensure exceptional delivery.


Do you have any questions about our slewing bearing? Maybe you can find the answer below. If the answer below does not solve your problem, please contact us and our engineer will answer it for you.

1. Where is your slewing bearing manufactured?
Our slewing bearings are all manufactured in China. We not only have the ability to design and produce slewing bearings but the quality can also be guaranteed. At the same time, our slewing-bearing price is more favorable.

2. I don’t know which slewing bearing to use, can you choose for me?
Yes, of course, Each model has a parameter list on the website. You can choose the suitable slewing bearing according to these parameter lists. If you don’t know how to choose, you can get in touch with us and our engineers will work with you to choose the suitable product. We can also design a new slewing bearing solution for you according to your equipment.

3. Can I get your product catalog?
You can get our product catalog in the download or contact us, we will send the product catalog to you by email or other ways.

4. Can you customize products?
Yes, we can. Our engineers have very rich experience in slewing bearing design. On the customized slewing bearing page, you can see some special customized products designed by our engineers. These design solutions meet the special needs of many customers. Our engineers can also work with you to design a new slewing bearing.

5. Can you provide accessories?
Yes, we can provide matching spare parts such as motors, hydraulic motors, and encoders that are compatible with slewing bearings.

6. Can you provide a 3D model?
Yes. All our slewing bearings have 3D models, you can contact us to get them. At the same time, we can also provide CAD files and PDF files.

7. How long is your slewing bearing warranty period?
Our slewing bearing warranty time is 12 months. When you install, use, and store the slewing bearing, please refer to the slewing bearing instruction manual.

8. Can you choose the color of your slewing bearing?
Yes. Our slewing bearing is available in many colors. If you have special requirements, please tell our sales engineers, we are happy to provide services for you.


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