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Improved Lubrication and Lubricant Application
Published in Heinz P. Bloch, Allan R. Budris, Pump User’s Handbook, 2021
Heinz P. Bloch, Allan R. Budris
The life of a rolling element bearing running under good operating conditions is usually limited by fatigue failure rather than by wear. Under optimum operating conditions, the fatigue life of a ball bearing is determined by the number of stress reversals and by the cube of the load causing these stresses. As examples, if the load on the ball bearing is doubled, the theoretical fatigue life is reduced to one-eighth. This is graphically shown in Figure 9-1. Also, if speed is doubled, the theoretical fatigue life is reduced to one-half.
Lubrication Theory
Published in Ryan Cruzan, Manager’s Guide to Preventive Building Maintenance, 2020
There are two main categories of bearings. The first is known as “plain” or “sleeve” bearings. The second type is “rolling element” bearings. The most familiar type of rolling element bearing is probably the ball bearing.
Lubricants and Lubrication
Published in Ahmed Abdelbary, Extreme Tribology, 2020
The major advantages of a grease-lubricated rolling-element bearing are simplicity of design, ease of maintenance and minimal weight and space requirements. On the other hand, the limitation of using greases in lubrication is heat and speed. Grease is greatly limited in the amount of heat it will or can dissipate as compared with oil. Therefore, grease lubrication is typically restricted to low and medium capacity gears and bearings operating in short or intermittent intervals. Gear motors and all types of small and miniature gears, such as power tools, household and office equipment, and automotive servo drives are the primary applications for grease.
Influence of Pits on the Tribological Properties and Friction-Induced Vibration Noise of Textured Tapered Roller Bearings
Published in Tribology Transactions, 2023
Yueyong Wang, Yimin Zhang, Risheng Long
A tapered roller bearing (TRB) is a type of rolling element bearing. Because it can transmit the rotational motion of the system, it is the most reasonable solution to support combined loads (radial and axial) in a limited overall space (1, 2). It is widely used in wheel hubs, helicopter gearboxes, and machine tool spindles (3). As a separable bearing, it has the advantages of easy installation, easy follow-up maintenance, and high maintenance efficiency. Frictional wear and friction-induced vibration noise between the moving parts (outer ring, inner ring, rolling elements, and cages) of rolling element bearings are unavoidable, resulting in a huge waste of energy and material loss. To reduce this waste and loss, it is important to improve the wear resistance of tapered roller bearings (4).
Self-adaptive Multi-population Rao Algorithms for Engineering Design Optimization
Published in Applied Artificial Intelligence, 2020
Figure 8 shows the schematic diagram of a rolling element bearing. This problem is taken from Yildiz, Abderazek, and Mirjalili (2019). The maximization of the dynamic load capacity of the rolling element bearing is the objective of this problem while satisfying nine non-linear inequality design constraints (given as Problem 4 in Appendix B). This problem consists of 10 variables out of which five are design variables, namely the pitch diameter of bearing as Dm, the diameter of balls as Db, the number of balls as Z, the curvature coefficient of inner and outer raceway as fi and fo, and five variables are constraint parameters such as KDmin, KDmax, β, ε, and e. The number of balls Z is an integer variable and the remaining nine variables are continuous. The previous researchers had converted this problem into a minimization problem by multiplying the objective function by −1. Hence, in this paper also the objective function as presented by the previous researchers is considered.
An Investigation on Reasons Causing Inferiority in Unlubricated Sliding Wear Performance of 60NiTi as Compared to 440C Steel
Published in Tribology Transactions, 2019
Khashayar Khanlari, Maziar Ramezani, Piaras Kelly, Peng Cao, Thomas Neitzert
Low elastic modulus and large elastic deformation of 60NiTi results in an expansion of the contact area when this material is under localized loads. This subsequently leads to a drop in peak Hertz contact stress (2, 5, 10, 11). The combination of this with the high compressive strength of 60NiTi results in a great capacity of this intermetallic to tolerate high local static loads before experiencing any permanent deformation (2, 5, 10, 11). DellaCorte et al. performed extensive static indentation tests on 60NiTi and other typical bearing steels. In these tests, to mimic ball bearing denting behaviour, Si3N4 balls with 12.7mm diameter were used as indenters. Based on the results obtained from these experiments, 60NiTi can take ∼4 times the load taken by 440C steel before experiencing the same threshold dent depth of about 0.6 μm (8, 10, 11). Other than resiliency, 60NiTi shows a superior resistance to corrosion than 440C steel as it is immune to atmospheric rusting (10). The combination of these properties has resulted in the emergence of this superelastic intermetallic as a new rolling element bearing material (8).