Product Description
Radial spherical plain bearings have an inner ring with a sphered convex outside diameter and an outer ring with a correspondingly sphered but concave inside surface. Their design makes them particularly suitable for bearing arrangements where alignment movements between shaft and housing have to be accommodated, or where oscillating or recurrent tilting or slewing movements must be possible at relatively slow sliding speeds, often accompanied with heavy loads.
To better understand frequently used plain bearing, definitions are provided in fig. 1 .
Spherical plain bearing
1 Outer ring 2 Sliding contact surfaces 3 Seal 4 Inner ring 5 Lubrication hole 6 Lubrication groove
Advantages
Design advantages inherent to spherical plain bearings include the ability to:
• accommodate misalignment
• virtually eliminate edge stresses and excessive stressing of adjacent components
• accommodate deformation of surrounding components in operation
• accommodate wide manufacturing tolerances and the use of cost-effective, welded assemblies
Radial Spherical Plain Bearings
Designs and variants
All the products listed below belong to standard assortment:
• radial spherical plain bearings requiring maintenance
• maintenance-free radial spherical plain bearings
• angular contact spherical plain bearings
• thrust spherical plain bearings
Radial spherical plain bearings requiring maintenance
Features
A characteristic feature of steel/steel radial spherical plain bearings is the outer ring, which is intentionally fractured so that it can be sprung apart to enable the inner ring to be inserted (fig.1). Therefore, these bearings are non-separable and easy to handle.
The bearings are manganese phosphated and the sliding contact surface is then treated with a running-in lubricant. This reduces friction and wear during the running-in period. To facilitate lubrication, all bearings, with the exception of some small sizes, have an annular groove and two lubrication holes in both the inner and outer rings.
Heavy-duty spherical plain bearings (fig. 2) are manufactured with the multi groove system and are fitted with a LS heavy-duty (triple-lip) seal on both sides (fig. 3). As their name implies, these bearings are an excellent solution for applications under extreme environments and operating conditions such as:
● heavy alternating loads
● shock loads
● heavy static loads
A standard assortment of heavy-duty spherical plain bearings is listed in the product table. On request, NEWORLD can manufacture and supply also other radial spherical plain bearings with the multi-groove system (designation suffix ESL).
Dimensions
The dimensions of spherical plain bearings in the GE, GEH and GEG series are in accordance with ISO 12240-1:1998. Bearings in the GEM series, which have an extended inner ring, have a non-standard inner
ring width, but otherwise have the same dimensions as GE series bearings. Inch spherical plain bearings in the GEZ series are in accordance with the American Standard ANSI/ABMA Std. 22.2-1988.
Materials
The inner and outer rings of steel/steel radial spherical plain bearings are made of bearing steel. They are through-hardened, ground and phosphated. The sliding contact surfaces are treated with a running-in lubricant.
Depending on the bore diameter, metric bearings with a 2RS suffix have a double-lip seal made of a polyester elastomer or acrylonitrile-butadiene rubber on both sides of the bearing. Inch bearings with a 2RS suffix have a double-lip seal made of polyurethane on both sides of the bearing.
Metric and inch bearings with the designation suffix -2LS have a sheet steel reinforced, triple-lip heavy-duty seal made of acrylonitrile-butadiene on both sides of the bearing.
Permissible operating temperature range
Open steel/steel radial spherical plain bearings have a permissible operating temperature range
of –50 to +200 °C, but their load carrying capacity will be reduced at temperatures above +150 °C. Bearings for higher temperature applications up to 300 °C, can be produced on request.
For sealed bearings, the permissible operating temperature range is limited by the seal material:
● –20 to +80 °C for inch RS seals
● –30 to +130 °C for metric RS seals with a bore diameter d < 320 mm
● –35 to +100 °C for metric RS seals with a bore diameter d ≥ 320 mm
● –55 to +110 °C for LS seals
The operating temperature range of the grease used to lubricate the bearings must also be taken
into consideration.
Maintenance-free radial spherical plain bearings
NEWORLD manufactures maintenance-free radial spherical plain bearings in a variety of designs and a wide range of sizes. Three sliding contact surface combinations are available:
● Steel/PTFE sintered bronze, designation suffix C
● Steel/PTFE fabric, designation suffix TX
● Steel/PTFE FRP, designation suffix F
The different designs of maintenance free radial spherical plain bearings are listed in table 3. Their design depends on the size and series, with the main differences being the material or the design of the outer ring.
Dimensions
The dimensions of metric maintenance-free radial spherical plain bearings are in accordance with ISO 12240-1:1998. The dimensions of inch bearings in the GEZ series are in accordance with ANSI/ABMA Std. 22.2-1988.
Materials
The materials for the inner ring, outer ring, sliding layer and seals, where applicable, are listed in table 3.
Permissible operating temperature range
The permissible operating temperature range of maintenance-free radial spherical plain bearings depends on the sliding contact surface combination and the material of the seals ( table 3). However, if the load carrying capacity of the bearings is to be fully exploited, the temperature range must be narrowed. Depending on the application, it is possible to operate at temperatures above the upper limit for brief periods.
Angular contact spherical plain bearings
As their name implies, the sliding contact surfaces of angular contact spherical plain bearings are spherical in shape and inclined at an angle to the bearing axis (fig. 1). Consequently, these bearings are well suited for accommodating combined (radial and axial) loads. Single angular contact spherical plain bearings can only accommodate axial loads acting in one direction. These bearings can be separated, enabling the rings to be mounted separately.
NEWORLD manufactures steel/PTFE FRP (fibre reinforced polymer containing PTFE) maintenance-free angular contact spherical plain bearings as standard. Designs with other sliding surface combinations are available on request.
Dimensions
The boundary dimensions of NEWORLD angular contact spherical plain bearings are in accordance with ISO 12240-2:1998.
Materials
The inner and outer rings of NEWORLD angular contact spherical plain bearings are made of bearing steel that has been through-hardened and ground. The sliding layer of fibre reinforced polymer, containing PTFE, is injection moulded onto the outer ring (fig. 4).
Permissible operating temperature range
Spherical plain bearings with a steel/PTFE FRP sliding contact surface combination can be used for operating temperatures ranging from –40 to +75 °C. For brief periods, temperatures up to 110 °C can be tolerated, however keep in mind that the load carrying capacity of the bearing will be reduced at temperatures that exceed 50 °C. For additional information, contact the NEWORLD application engineering service.
Special designs
Special operating conditions may require angular contact spherical plain bearings with a steel/PTFE fabric or steel/steel sliding contact surface combination. These bearings are available on request, whereas those with a steel/PTFE fabric sliding surface combination are available in metric sizes. Bearings with a steel/steel sliding surface combination are available in both metric and inch sizes.
Bearings with a maintenance-free steel/PTFE fabric sliding contact surface combination (fig. 5) should be used when lubricant-free operation is specified. These bearings can accommodate heavy loads, preferably in a constant direction.
Steel/steel bearings ( fig. 6) are typically used in applications where operating temperatures or load frequencies are high, or where heavy or shock loads occur. The sliding surface of the inner ring is hard chromium plated and coated with a lithium base grease. To operate properly, steel/steel bearings must be provided with an adequate supply of lubricant. Depending on the operating conditions, the sliding surface of the outer ring may be equipped with various multi-groove patterns (figs. 7 and 8).
Upon request, inch steel/steel angular contact spherical plain bearings are also available as double direction angular contact spherical plain bearings. Double direction bearings can be used instead of two angular contact bearings in a face-to face arrangement, or as a high capacity radial bearing. Double direction angular contact spherical plain bearings consist of two outer rings and a standard inner ring. NEWORLD supplies these bearings with (GEZPR .. S series) or without (GEZP .. S series) a shim between the two outer rings. The shim simplifies installation and optimizes axial internal clearance within the bearing (fig. 9).
Thrust spherical plain bearings
Thrust spherical plain bearings have a convex spherical surface on the shaft washer and a corresponding concave spherical surface in the housing washer (fig. 1). They are intended to accommodate primarily axial loads but can also accommodate combined (radial and axial) loads.
The radial load component of a combined load should not exceed 50% of the axial load component. When radial loads are larger, it is advisable to combine thrust bearings with radial bearings in the GE dimension series ( fig. 2). Thrust spherical plain bearings are separable, e.g. shaft and housing washers can be mounted separately.
NEWORLD manufactures thrust spherical plain bearings with the maintenance-free steel/PTFE FRP (fibre reinforced polymer containing PTFE) sliding contact surface combination as standard. Other sliding surface combinations are available on request.
Dimensions
The principal dimensions of thrust spherical plain bearings are in accordance with ISO 12240-3:1998.
Materials
Shaft and housing washers for thrust spherical plain bearings are made of bearing steel that has been through-hardened and ground. The sliding surface of the shaft washer is hard chromium plated and coated with a lithium base grease. The sliding layer of fibre reinforced polymer, containing PTFE, is injection moulded onto the housing washer.
Permissible operating temperature range
Thrust spherical plain bearings with a steel/PTFE FRP sliding contact surface combination can be used for operating temperatures ranging from –40 to +75 °C. For brief periods, temperatures up to 110 °C can be tolerated, however keep in mind that the load carrying capacity of the bearing will be reduced at temperatures that exceed 50 °C. For additional information, contact the NEWORLD application engineering service.
Special designs
Special operating conditions may require thrust spherical plain bearings with a steel/steel or steel/PTFE fabric sliding contact combination, which are available on request.
Steel/steel bearings (fig. 3) are typically used in applications where operating temperatures or load frequencies are high, or where heavy loads or shock loads occur. Steel/steel bearings must be provided with an adequate supply of lubricant. Depending on the operating conditions, the sliding surface of the outer ring may be equipped with various multi-groove patterns.
Bearings with a maintenance-free steel/PTFE fabric sliding contact surface ( fig. 4) should be used when lubricant-free operation is specified. These bearings can accommodate heavy loads, preferably in a constant direction.
Application
Long service life, high reliability and minimal maintenance are some of the features of NEWORLD spherical plain bearings. NEWORLD’s wide assortment of spherical plain bearings is versatile enough to be used in a variety of applications that encompass almost all sectors of industry, including:
• agriculture
• construction
• forklift trucks
• material handling
• metals
• mining
• railways
• trucks
• wind energy
