Product Description
Generally, slewing bearings are large-size rolling bearings that can accommodate axial, radial and moment loads acting either singly or in combination and in any direction. They can perform both slewing (oscillating) movements as well as rotational movements.
Basically, a slewing bearing (fig. 1) consists of an inner ring (a), an outer ring (b) and rolling elements − balls (c) or cylindrical rollers − that are separated by polyamide spacers (d). The rings, one of which usually incorporates a gear (e), are provided with holes (f) to accommodate attachment bolts. The holes may be threaded. Generally, only the raceways in the rings (h) are hardened and precision-ground. Integral seals (g) made of acrylonitrile-butadiene rubber (NBR) keep the lubricant in, and contaminants out of the bearing. Slewing bearings are relubricated Slewing bearings through grease fittings (i) to reduce maintenance and operating costs.
Single row slewing bearings
NEWORLD manufactures slewing bearings in a number of types and variants. The most common bearings available from stock or within short lead times are:
• single row four-point contact ball slewing bearings
• single row crossed cylindrical roller slewing bearings
• with an external gear (a)
• with an internal gear (b)
• without a gear gear (c)
Single row four-point contact ball slewing bearings
Light series four-point contact ball slewing bearings (fig. 1)
Medium size four-point contact ball slewing bearings (fig. 2)
Single row crossed cylindrical roller slewing bearings
Medium size crossed cylindrical roller slewing bearings (fig. 3)
Multi-row row slewing bearings
Double row ball slewing bearings
Double row four-point contact ball slewing bearings offer advantages for applications where the associated components may not be able to provide the level of stiffness or accuracy required by other types of slewing bearings.
These bearings consist of two one-piece rings and two independent rows of balls. The ball set can be a full complement design or separated by a window-type steel cage or poly amide spacers. The bearings are normally preloaded and fitted with integral lip seals.
Double row four-point contact ball slewing bearings can be manufactured:
• without a gear
• with an internal gear (fig. 1)
• with an external gear
Double row cylindrical roller slewing bearings
Double row cylindrical roller slewing bearings can accommodate heavy axial and radial loads as well as high tilting
moments, which makes them particularly suitable for heavy-duty applications.
The bearings consist of two one-piece rings and two independent rows of rollers. The rollers are inserted into the bearing via two holes in one of the two rings and are separated by polyamide spacers. After loading the roller set, the holes are closed with a plug that conforms to the raceway contour. These bearings are normally preloaded and fitted with integral lip seals.
Double row cylindrical roller slewing bearings can be manufactured:
• without a gear
• with an internal gear (fig. 2)
• with an external gear
Triple row roller slewing bearings
Triple row roller slewing bearings are an excellent choice for heavily loaded applications. They provide the highest load ratings possible and can accommodate very heavy loads and high tilting moments.
These bearings are combined cylindrical roller radial/thrust bearings. They consist of one one-piece and one two-piece ring as well as two roller sets to accommodate axial loads, and one roller set to accommodate radial
loads. Polyamide cages separate the axially loaded rollers. The bearings are not preloaded and have integral lip seals.
Triple row roller slewing bearings can be manufactured:
• without a gear
• with an internal gear ( fig. 3)
• with an external gear
Triple row roller slewing bearings are sensitive to the deflections of associated components. As a result, an extremely stiff and accurately manufactured support structure is required if the bearing is to achieve maximum service life.
Combined slewing bearings
Combined cylindrical roller/ball slewing bearings
Combined cylindrical roller/ball slewing bearings can accommodate the same heavy axial loads as triple row roller slewing bearings in one direction only, but cannot accommodate the same degree of tilting moments. They are suitable for heavy- duty applications, but are as sensitive as triple row bearings to surface imperfections.
Combined cylindrical roller/ball slewing bearings consist of two one-piece rings and normally have axial internal clearance. The balls are inserted into the bearing via a hole in one of the two rings and are separated by polyamide spacers.
Combined cylindrical roller/ball slewing bearings can be manufactured:
• without a gear
• with an integral gear
• with an external gear (fig. 4)
Wire race slewing bearings
NEWORLD offers a wide range of single row as well as multi-row ball or cylindrical roller wire race slewing bearings. Single row four point contact ball wire race slewing bearings (fig. 5) and single row crossed cylindrical roller wire race slewing bearings ( fig. 6) are the most widely used slewing bearing types and normally consist of:
• a one-piece and a two-piece bearing ring made of aluminium
• four through-hardened wire inserts made of bearing steel, forming the raceways
• a cage guided rolling element assembly
Single row wire race slewing bearings are recommended for lightweight, precision applications. They are 70% lighter than similarly sized all-steel bearings, and can accommodate light to normal loads and significant tilting moments. Furthermore, the design of the wire inserts makes these bearings relatively insensitive to support surface imperfections.
Multi-row wire race slewing bearings, such as double or triple row roller bearings, are available for heavier load applications.
Wire race slewing bearings can be manufactured:
• without a gear
• with an internal gear
• with an external gear
Application
Application in Mining and quarrying
hydraulic excavators
Other application area:
• access platforms
• bucket wheel excavators
• conveyor booms
• cranes of all types
• small, medium and large excavators
• indexing tables
• ladle turrets
• offshore applications
• robots
• railway bogies
• rotary platforms
• stackers
• solar mirrors
• tunnel boring machines
