How Do Oscillation Angle, Frequency and Sliding Speed Determine the Life of a Spherical Plain Bearing?
A spherical plain bearing wears where its two surfaces slide on each other, so its life depends on how far and how fast they slide, and how hard they press. The swing angle and the swing rate set the sliding speed. The load and the size of the bearing set the contact pressure. Pressure times […]
How Much Radial Internal Clearance Should a Spherical Plain Bearing Have, and How Do You Check It?
Radial internal clearance is the small play a spherical plain bearing has before it is fitted: how far the inner ring can be moved sideways inside the outer ring. Most bearings are made to the normal group, called N or CN. A tighter group (C2) is for arrangements that want very little play. A looser […]
What Temperature Limits Apply to Steel-on-Steel and PTFE-Lined Spherical Plain Bearings?
There is no single limit. Published figures differ by maker and by design. As a rough picture, one maker rates its standard bearings at −10 °C to +80 °C without restriction, a catalogue gives −50 °C to +150 °C for a steel/PTFE fabric type, and aerospace liner systems reach 200 °C to 330 °C. The […]
How Do You Choose Between a Steel-on-Steel and a Maintenance-Free (PTFE-Lined) Spherical Plain Bearing?
Choose by what the sliding surface needs. A maintenance-free, PTFE-lined bearing suits a pivot you cannot grease, as long as the load, sliding speed, temperature and dirt stay inside the liner’s published limits. A steel-on-steel bearing suits heavy, alternating or shock loads, as long as your machine can keep delivering the specified grease. Neither type […]
How Do You Tell Why a Spherical Plain Bearing Failed: Wear, Galling, Fretting, Flaking or Liner Delamination?
Read three things together: where the damage is, what it looks like, and what the bearing was doing. Scored surfaces with metal smeared from one side to the other point to galling, which is a lubrication failure. Reddish dust at the fit lines points to fretting. Dents on the ball point to impact or overload. […]
How Much Misalignment and Axial Load Can a Spherical Plain Bearing Take, and When Do You Need an Angular Contact Bearing?
A spherical plain bearing is built to carry load mainly in the radial direction and to tilt a limited number of degrees each way. Both limits are set by the bearing’s series and size, so read them from the maker’s table. Going past the tilt limit damages the bearing. For a load that pushes along […]
How Do You Install a Spherical Plain Bearing in a Housing Without Damaging It?
Keep it clean, line it up square with the bore, and push on the ring that is going in, never through the ball. Use a press, not a hammer, and give the parts a lead-in chamfer. Where the fit is tight, use a temperature difference rather than force. Hold the bearing in place with the […]
Open or Sealed (ES or 2RS)? Which Seals and Materials Suit Dusty, Wet, Corrosive or Washdown Conditions?
In dust or other contamination, choose a sealed type (2RS), and add a boot or wiper where washdown jets reach the joint. The seal keeps dirt out and grease in, but it does not make the bearing waterproof. For corrosive or wet service, the ring and ball material, the sliding pair and a grease that […]
How Do You Size a Spherical Plain Bearing: Load Ratings, Safety Factor, Shock and Reversing Loads?
Sizing is three checks in a row. First turn the radial and axial loads into one equivalent load P. Then check the static rating C₀ against P with a safety factor. Then, if the bearing swings under load, check the contact pressure and sliding speed (pV) and the life by the maker’s method. The worked […]
What Grease, How Much and How Often for a Steel-on-Steel Spherical Plain Bearing, and How Do the Lubrication Holes and Grooves Work?
Use a lithium-soap extreme-pressure grease, grease the bearing while it is unloaded, and keep adding until fresh grease shows between the inner and outer rings. How often depends on what the duty does to the grease: heavy one-direction load, small swing angle, heat, dirt and water all shorten it. As a guide, one maker puts […]
What Do GE, GEH, GEG and GEEW Mean on a Spherical Plain Bearing, and What Do the Suffixes ES, 2RS and TX Mean?
The letters are a maker’s shorthand laid on top of the ISO 12240-1 dimension series, which fixes how outside diameter and width relate to the bore. GE is the common metric radial type. GEG, GEH and GEEW point to a wider or larger-diameter series, or to an extended inner ring. The suffixes describe details: E […]
When Should a Spherical Plain Bearing Be Replaced: Measuring Play, Inspection and Wear Limits?
Replace it when it has used up the play, torque, noise or condition you decided you can accept. There is no single wear limit for all spherical plain bearings, so set your own limit with the maker’s figures before the bearing goes into service. Check by unloading the joint, cleaning it, and moving the ball […]