A containing is a system element that supports a book, another moving machine element. While delivering the load, it allows a relative movements between the members ‘ call surfaces. While doing so, a certain amount of power is lost in overcoming frictional resistance as a result of the comparative movement between the call surfaces. We need to examine the types of Bearings, style, and supplies used for bearings briefly. In the previous article, we discussed the different types of Bearings. Sliding Personal Bearings are a type of holding that is referred to as hydrodynamically greased bearings. In this article, let us discuss the Coefficient of Friction for Journal Bearings.

A little thought may reveal that a certain amount of power is lost in overcoming frictional weight as a result of the comparative activity between the contact surfaces. If the scratching surfaces come into direct contact, there will be quick use. A level of fluid may be provided to minimize frictional opposition and wear and, occasionally, take away the heat generated. The fluid used to distinguish the blog and holding is usually a nutrient oil refined from hydrocarbon, but veggie oils, silicone oils, greases, etc., may be used.

Friction factor for book joints

The Coefficient of Friction is generally defined as the ratio of the viscous force that prevents two areas from moving in contact with one another and the normal pressure that forces two areas together. The Greek letter mu ( ) is typically used as a symbol for it.

The experimental relationship established by McKee based on the experimental data may be used to determine the coefficient of friction for well-lubricated whole book joints.

Coefficient of friction,

Where
Z = Absolute viscosity of the lubricant, in kg / m-s
N = Speed of the journal in r.p.m.,
p = Bearing pressure on the projected bearing area in N/mm2 = Load on the journal ÷ l×d
d = Diameter of the journal
c = Diametral clearance
k = Factor to correct for end leakage. It depends upon the ratio of length to the diameter of the bearing (i.e. l / d). = 0.002 for l / d ratios of 0.75 to 2.8.

To maintain a healthy margin between working conditions and the point of film breakdown, ZN / p’s operating values may be compared with those provided in the following table.

Machinery Bearing Maximum bearing
pressure ( p ) in N/mm2		 Running beliefs
Absolute Viscosity ( Z ) in kg/m- s ZN/p
( Z in kg/m- s p in N/mm2 )		 c / d l / d
Automobile and airplane machines Main  5.6 – 12 0.007 2.1 – 0.8–1.8 
Crank button 10.5 – 24.5 0.008 1.4 – 0.7–1.4 
Elbow button 16 – 35 0.008 1.12 – 1.5 – 2.2
Four strokes- Gas and oil machines Main
Crank button
Elbow wire		 5 – 8.5
9.8 – 12.6
12.6 – 15.4		 0.02
0.04
0.065 		 2.8
1.4
0.7 		 0.001 0.6 – 2
0.6 – 1.5
1.5 – 2
Two strokes Gas and oil vehicles Main
Crank button
Elbow wire		 3.5 – 5.6
7 – 10.5
8.4 – 12.6		 0.02
0.04
0.065 		 3.5
1.8
1.4 		 0.001 0.6 – 2
0.6 – 1.5
1.5 – 2
Marine gas engines Main
Crank button
Elbow wire		 3.5
4.2
10.5 		 0.03
0.04
0.05 		 2.8
2.1
1.4 		 0.001 0.7 – 1.5
0.7 – 1.2
1.2 – 1.7
Stable, slow- speed vapor engines Main
Crank button
Elbow wire		 2.8
10.5
12.6 		 0.06
0.08
0.06 		 2.8
0.84
0.7 		 0.001 1–2
0.9 – 1.3
1.2 – 1.5
Stationary, substantial- speed vapor engine Main
Crank button
Elbow wire		 1.75
4.2
12.6 		 0.015
0.030
0.025 		 3.5
0.84
0.7 		 0.001 1.5 – 3
0.9-1.5
13 – 1.7
Reciprocating compressors and turbines Main
Crank button
Elbow wire		 1.75
4.2
7.0 		 0.03
0.05
0.08 		 4.2
2.8
1.4 		 0.001 1 – 2.2
0.9 – 1.7
1.5 – 2.0
Steam trains Driving wheel
Crank button
Elbow wire		 3.85
14
28 		 0.10
0.04
0.03 		 4.2
0.7
0.7 		 0.001 1.6 -1.8
0.7 -1.1
0.8 – 1.3
Railway trucks
Steam windmills		 Axle
Main		 3.5
0.7-2		 0.1
0.002 – 0.016		 7
14		 0.001
0.001 		 1.8 – 2
1–2 
Producers, vehicles,
spinning sends		 Rotor  0.7 – 1.4 0.025 28 0.0013 1–2 
Transmission bolts Mild- fixed
Self -aligning
Heavy 		 0.175
1.05
1.05 		 0.025- 0.060 7
2.1
2.1 		 0.001 2–3
2.5 – 4
2– 3
Equipment equipment Main  2.1 0.04 0.14 0.001 1–4 
Hitting and cutting models Main
Crank button 		 28
56 		 0.1  —  0.001 1–2 
Rolling Mills Main  21 0.05 1.4 0.0015 1–1.5