Slewing rings

Rogalla  Slewing Rings

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Slewing Rings

Simultaneous transmission of axial and radial forces

Slewing rings are versatile, large-diameter antifriction bearings that transmit axial and radial forces while at the same time absorbing the resulting tilting moments. Their high load-carrying capacity makes them ideally suited for applications involving high stresses.

Slewing rings are not considered ball or roller bearings since, unlike the latter, they are not mounted on a shaft or in a housing but are instead installed axially by screwing the bearing rings to the adjacent structure. Slewing rings are normally mounted in a horizontal position, but there are also applications and design forms where they are suspended or mounted vertically.

The basic structure of a slewing ring consists of one outer and one inner ring, in the case of single-row designs, and up to three rings in the case of multi-row designs, as well as rolling elements which are held at a distance and guided by spacers and a sealed raceway system with grease lubrication.

Slewing rings differ according to the shape of their rolling elements and the principle of power transmission, coming in the form of ball bearing slewing rings and roller bearing slewing rings. Special forms are also available.

Rogalla Slewing rings

Slewing Rings in Practice

Slewing rings are used as important connecting elements in many applications and a wide range of machines and systems, such as in:

  • the extraction of raw materials
  • special civil engineering and road construction
  • earthworks 
  • materials handling
  • vehicle construction
  • automation technology and robotics
  • aerospace technology
  • the production of building materials
  • radar, satellite and telescope systems
  • medical technology and
  • the machine tool industry

to mention just a few.

Our product range includes slewing rings in dimensions from Ø 200 mm to Ø 5000 mm.

Types and Forms of Slewing Ring

| without toothing |

Series 2000 Single-row ball bearing slewing rings without toothing

| with external toothing |

Series 2000 Single-row ball bearing slewing rings external toothing

| with internal toothing |

Series 2000 Single-row ball bearing slewing rings internal toothing
  • Slewing rings are divided into three types, regardless of the form of their rolling elements and bearings.
  • From these three basic forms are derived further bearing forms which are optimally tailored to an extremely broad spectrum of uses and applications.
  • Standard slewing rings or catalogue types in a wide range of dimensions are available to the user, but the vast majority are customer-specific solutions developed in conjunction with the customer.

Our Delivery Programme

includes slewing rings in dimensions from Ø 300 mm to Ø 5000 mm.

Series 2000 - Profile bearings (light series)

  • Single-row ball bearing slewing rings without toothing
  • Single-row ball bearing slewing rings with external toothing
  • Single-row thrust ball bearing slewing rings with internal toothing

Series 3000 – Four-point bearings

  • Single-row ball bearing slewing rings without toothing
  • Single-row ball bearing slewing rings with external toothing
  • Single-row thrust ball bearing slewing rings with internal toothing

Series 4000 - Eight-point bearings (double-axis bearing)

  • Double-row ball bearing slewing rings without toothing
  • Double-row ball bearing slewing rings with external toothing
  • Double-row ball bearing slewing rings with internal toothing

Series 5000 - Cross roller bearings

  • Single-row roller bearing slewing rings without toothing
  • Single-row roller bearing slewing rings with external toothing 
  • Single-row roller bearing slewing rings with internal teeth 

Series 7000 - Thrust radial roller bearings

  • Three-row roller bearing slewing rings without toothing
  • Three-row roller bearing slewing rings with internal teeth
  • Three-row roller bearing slewing rings with external toothing

Series 8000 - Special forms of slewing ring

  • Special forms of ball and roller bearing slewing ring for particular applications.
  • Single, double and triple-row as well as combined forms (ball-roller bearing slewing rings)
  • Without or with toothing as well as special toothing and shapes

Nomenclature of ROTIS Slewing Rings

Nomenclature of ROTIS slewing rings

Structure of a Slewing Ring

using the example of a single-row ball bearing slewing ring:

Structure of a slewing ring

 

1. Inner Ring

2. Outer Ring

3. Spacer

4. Ball

5. Seal

  • Our ROTIS slewing rings are manufactured from high-quality alloy steels in accordance with the latest development and production standards. The seamlessly rolled rings are supplied exclusively by leading European manufacturers. Technological progress and project developments mean that a wide range of designs and forms of slewing ring in the range of 200 mm to 5000 mm Ø can be successfully manufactured today.

Ring material

Slewing rings are made of low-alloyed heat-treatable steels. Most of those used are seamlessly rolled rings made of C45+QT and 42CrMo4+QT according to EN 10083-2 and EN 10083-3 or 10083-3 with stricter requirements in order to guarantee a temperature application range of -20°C.

  • ROTIS uses a wide range of steels which, due to their different structural characteristics (normalised or quenched and tempered), can be used for a very broad spectrum of applications, with quenched and tempered steel being much more suitable than normalised steel for the manufacture of both slewing rings and gears exposed to greater loads. Slewing rings are normally manufactured from C45 or 42CrMo4.

The following table shows the designations for the two most widely used slewing ring materials by country and their respective material number according to EN 10083-2:2006 and EN 10083-3:2006:

COUNTRY MATERIAL KEY    
GERMANY DIN Ck45 42CrMo4
ITALY UNI C45 42CrMo4
SPAIN UNE C45K (F1140) 42CrMo4 (F8232)
JAPAN JIS S45C SNB7
SCHWEDEN SSSTAHL 1672 2244
USA AISI 16B45 4142

However, the use of other materials is possible for special applications or where there are particular functional requirements, such as use in very humid or salty environments.

  • Stainless steel (e.g., stainless martensitic chromium steel 1.4034),
  • hardened steel alloys,
  • steel hardened in controlled atmospheres,
  • carburized or nitrided steel,
  • special steel for extremely low temperatures,
  • light metal alloys based on aluminium.

Rolling elements

In the case of ball bearing slewing rings, the rolling elements used as standard comply with DIN 5401; in the case of roller bearing slewing rings, cylindrical rollers conforming to DIN 5402 are used.

  • The material for the rolling elements is 100Cr6 to ISO 683-17, but other materials such as stainless steel 1.4125 may be used on request.

Spacers

The elements used for rolling element separation (figures 1 to 5) are made of PA6, PA1010 or PVC, depending on the application and requirements.

  • For higher temperatures above 70°C or other special applications, spacers made of brass or spacer cages made of steel S355J2G3 are used. Other materials may also be used, depending on requirements.
Standard spacer version for ball bearing slewing rings

Standard spacer version for ball bearing slewing rings

Band cage for ball bearing slewing rings

Band cage for ball bearing slewing rings

Axial roller spacer cage

Axial roller spacer cage

Radial and axial roller spacers

Radial and axial roller spacers

Cross roller spacers

Cross roller spacers

Seals

Slewing rings are generally designed with integral seals on both sides of the raceway system.

  • The seals are normally made of NBR profiles (nitrile butadiene rubber NBR 70) and provide reliable protection for the raceway systems against coarse contamination and ambient spray water. They also have the function of keeping the lubricant in the raceway systems.
  • For special applications in high-temperature areas, sealing profiles made of more temperature-resistant materials (fluororubber / fluorocarbon rubber) may be used.
  • Various sealing systems can be supplied (figure 6). The standard lip seals are sufficient for the use of slewing rings in general mechanical engineering or heavy mechanical engineering.
[Translate to English:] Dichtungssysteme

Sealing systems

Special sealing profiles and arrangements, labyrinth or multiple systems are used for specific requirements in difficult ambient conditions or in the case of mechanical stresses.

  • Despite the use of selected materials optimised for the application, the seal profiles are subject to unavoidable wear caused by environmental influences.
  • The seals must be routinely checked and replaced if necessary. The adjacent structure in the vicinity of the seals should be designed in such a way that there is no risk of mechanical damage from protruding or projecting components.

In addition, however, there are various applications and cases in closed drive systems where sealing is not required on one or both sides and the raceways are supplied and lubricated via the oil circuit of the system.

Lubrication system and lubricants

ROTIS standard slewing rings are equipped with a lubrication system for lubricating the raceway systems.

  • The lubrication connections are generally arranged radially, have a metric thread M10x1 and are provided with a standard lubrication nipple (straight form) conforming to DIN 71412.
Ball bearing slewing ring

Other versions of the lubrication system such as axial arrangements of the lubrication holes, alternative sizes and shapes of lubrication nipples or threads are possible. If the customer requires the slewing rings to be supplied without grease nipples, the lubrication holes are closed using standard plastic plugs.

  • As delivered, the raceway systems are initially greased with a quality lubricant that meets the performance requirements. Relubrication (grease lubrication) of the raceway systems can be carried out manually or, for ease of maintenance, via central lubrication systems.
  • In the standard form, the sealed slewing rings are filled with proven lithium-saponified EP multi-purpose greases from renowned manufacturers which are suitable for a relatively wide range of applications of mechanically high-load large-diameter antifriction bearings. Depending on availability, these are usually Castrol Spheerol™ EPL2 * or Shell Gadus™ S2 V220 ** for the raceway systems. For elevated temperature applications, Mobil Mobilith SHC™ 460 *** is the preferred option.

The lubricant industry offers a wide range of special lubricants for specific applications and uses in adverse ambient conditions. The suitable lubricant is determined in accordance with the respective performance requirement.

Tolerances

The general tolerances of the standard slewing rings conform to ISO 286-1 and ISO 286-2.

For applications with higher accuracy requirements, such as industrial robots, medical diagnostic and magnetic resonance therapy equipment, radar systems, etc., narrower tolerances and a higher degree of quality can be achieved.

Corrosion protection

A variety of options for protecting the machined metal surfaces from corrosion are available, depending on the requirements and ambient conditions.

  • Standard ROTIS slewing rings are protected with corrosion protection agents that have been proven in industrial use from established manufacturers and brands such as Castrol * or Tectyl® ****. The solvent-based standard corrosion protection applied is usually sufficient for a protection period of up to 12 months under normal storage and ambient conditions in temperate climates.
  • For longer-term corrosion protection or for storage in ambient conditions such as regions with salty sea air or higher ambient temperatures, a range of corrosion protection systems, coatings (zinc plating) and protective paints is available.
  • Unless otherwise agreed, slewing rings are packed in anti-corrosive paper and shrink wrapping as standard. The slewing rings are shipped in a horizontal position on suitable wooden structures (wooden pallets).
  • In order not to impair the functionality and useful life of slewing rings, the detailed descriptions, notes and specifications in the manufacturer's instructions for the transport, storage, installation, lubrication, and maintenance of large-diameter antifriction bearings must be observed.

Ball and Roller Bearing Slewing Rings and their special design forms

Ball bearing slewing rings

The rolling elements, which in this construction take the form of balls, describe the principle of power transmission (point contact) and give the bearing its name..

Ball bearing slewing rings

Roller bearing slewing rings

The rolling elements, which in this construction form cylindrical rollers, describe the principle of power transmission (line contact) and give the bearing its name.

Roller bearing slewing rings

Special design forms

In addition to the classic main constructions, there is a wide range of special forms for specific uses and applications.

Special design forms

All specifications and designations apply exclusively to slewing rings from the manufacturer ROTIS. Please note that the product specifications and features mentioned may deviate due to product changes and are therefore non-binding. The desired product specifications and features must therefore be expressly agreed in each individual case at the time of purchase.

* Castrol, Rustilo, and the Castrol logo are trademarks or registered trademarks of Castrol Limited (a BP Europa SE company and part of BP p.l.c.) or an affiliate of BP p.l.c.

** Shell, Gadus, and the Shell logo are trademarks or registered trademarks of Royal Dutch Shell plc, or an affiliate of Royal Dutch Shell plc.

*** Mobil, Mobilith and the Pegasus Design are trademarks or registered trademarks of Exxon Mobil Corporation or an affiliate of Exxon Mobil Corporation.

**** The Tectyl® trademark and all rights are owned by Ashland Consumer Markets (Valvoline™) or an affiliate of Ashland Global Holdings Inc.

Types and Forms of Slewing Ring / large-diameter Antifriction Bearings

Ball Bearing Slewing Rings

Series 2000 - Profile bearings (light series)

  • Single-row ball bearing slewing ring without toothing
  • Single-row ball bearing slewing ring with internal teeth
  • Single-row ball bearing slewing ring with external toothing

Series 3000 – Four-point bearings (heavy series)

  • Single-row ball bearing slewing ring without toothing
  • Single-row ball bearing slewing ring without toothing
  • Single-row ball bearing slewing ring with external toothing

Series 4000 - Double thrust bearings (eight-point bearings)

  • Double-row ball bearing slewing ring without toothing
  • Double-row ball bearing slewing ring with internal teeth
  • Double-row ball bearing slewing ring with external toothing

Roller Bearing Slewing Rings

Series 5000 - Cross roller bearings

  • Single-row roller bearing slewing ring without toothing
  • Single-row roller bearing slewing ring with internal teeth
  • Single-row roller bearing slewing ring with external toothing

Series 7000 - Axial radial roller bearings

  • Three-row roller bearing slewing ring without toothing
  • Three-row roller bearing slewing ring with internal teeth
  • Three-row roller bearing slewing ring with external toothing

Series 8000 - Special design forms of slewing ring

  • Special forms of ball and roller bearing slewing ring for special applications
  • Single, double and triple-row as well as combined designs (ball-roller bearing slewing rings)
  • Without or with toothing as well as special toothing and shapes