Types of cylindrical, spherical, tapered and ball designs Bearing Damage
Many different operating conditions can cause bearing damage. Those listed in this section make up the most commonly identified causes of damage for anti-friction bearings, including cylindrical, spherical, tapered and ball designs. Remember that you must follow proper bearing maintenance and handling practices to ensure your bearings achieve optimal performance levels.
Produces heats at localized points, happens when an electrical existing that travels through a bearing is broken at the contact surface areas in between the races and rolling components. Each time the existing is broken while passing in between the ball or roller and race, it produces a pit on both parts. Ultimately fluting establishes. As it ends up being much deeper, it develops sound and vibration. A high-amperage existing, such as a partial brief circuit, will trigger a rough, granular look. Heavy shocks of high-amperage charges will trigger more extreme damage, welding metal from the race to the ball or roller. These metal protrusions on the roller will, in turn, trigger a crater result in the race, creating more sound and vibration.
Abrasive Wear
Foreign particles cause wear and damage. Foreign particle contamination can cause abrasive wear, bruising or circumferential lining (grooving).
Fine foreign material in the bearing can cause excessive abrasive wear. Sand, fine metal from grinding or machining, and fine metal or carbides from gears wear or lap the rolling elements and races. In tapered bearings, the roller ends and cone rib wear to a greater degree than the races. This wear causes increased endplay or internal clearance, which can reduce fatigue life and create misalignment in the bearing. Abrasive wear also can affect other parts of the machine in which the bearings are used. The foreign par- ticles may get in through badly worn or defective seals. Improper initial cleaning of housings and parts, ineffective filtration or improper filter maintenance can allow abrasive particles to accumulate.
Pitting and Bruising
Difficult particles rolling through the bearing might trigger pitting and bruising of the rolling components and races. Metal chips or big particles of dirt staying in incorrectly cleaned up real estates can start early tiredness damage.
Typical external particles impurities consist of dirt, sand and ecological particles. Common reasons for internal particles contamination consist of wear from equipments, splines, seals, clutches, brakes, joints, poorly cleaned up real estates, and harmed or spalled parts. These tough particles take a trip within the lubrication, through the bearing and ultimately swelling (damage) the surface areas. Raised metal around the damages functions as surface-stress risers to trigger early spalling and minimize bearing life
Grooving
Exceptionally heavy wear from chips or metal particles can trigger grooving. These pollutants end up being wedged in the soft cage product and cut grooves in the rolling components. This condition creates inappropriate rolling contact geometry and can decrease life span.
Etching (or rust) stays among the most severe issues anti-friction bearings experience. Without sufficient security, the high degree of surface area finish on races and rolling components makes them vulnerable to deterioration damage from wetness and water.
Etching is usually triggered by condensate gathering in the bearing real estate from temperature level modifications. Wetness or water can get in through harmed, used or insufficient seals. Incorrectly cleaning and drying bearings when you eliminate them for examination likewise can trigger significant damage. After cleansing and drying or preparing bearings for storage, you need to coat them with oil or another preservative and cover them in protective paper. You ought to constantly save bearings, brand-new or utilized, in a dry location and keep them in initial product packaging to minimize the danger of fixed deterioration appearing prior to installing.
Discoloration
Metal-to-metal contact results in excessive bearing temperature.
High temperatures result in discoloration of the races and the roller.
In mild cases, the discoloration is from the lubricant staining the bearing surfaces. In severe cases, the metal is discolored from high heat.
Scoring and Peeling
Insufficient or complete lack of lubricant.
Selecting the wrong lubricant or lubrication type.
Temperature changes.
Sudden changes in running conditions.
Excessive Roller End Heat
Inadequate lubricant film results in localized high temperatures and scoring at the large ends of the rollers.
Total Bearing Lockup
High localized heat produces metal flow in bearings, altering the original bearing geometry and the bearing’s material.
This results in skewing of the rollers, destruction of the cage, metal transfer and complete seizure of the bearing.
Careful inspection of all bearings, gears, seals, lubricants and surrounding parts may help determine the primary cause of damage.
Spalling is the pitting or flaking away of bearing product. Spalling mostly takes place on the races and the rolling components. We reveal lots of kinds of "main" bearing damage throughout this referral guide that ultimately weaken into a secondary spalling damage mode.
We classify three distinct spalling damage modes:
Geometric Stress Concentration (GSC) Spalling
Causes for this type of damage mode include misalignment, deflection or edge loading that initiates high stress at localized regions of the bearing. It occurs at the extreme edges of the race/roller paths. It also can be the end result of shaft or housing machining errors.
Point Surface Origin (PSO) Spalling
Really high and localized tension creates this kind of damage mode. The spalling damage is generally from nicks, damages, particles, etching and hard-particle contamination in the bearing. It's the most typical kind of spalling damage, and it frequently looks like arrowhead-shaped spalls, propagating in the instructions of rotation.
Inclusion Origin Spalling
This damage happens when there's bearing product tiredness at localized locations of sub-surface, non-metallic additions following countless load cycles. An indication of this damage appears in the kind of localized, elliptically shaped spalls. Due to the enhancement of bearing steel cleanness throughout the previous twenty years, it might be not likely you will experience this kind of spalling.
