Introduction Types Of Journal Bearings Material Used For Journal Bearings Terms Used In Hydrodynamic Journal Bearings Bearing Characteristic Number And Bearing Modulus Design Procedure For Journal Bearings

1. Machine Design(2171909)
TOPIC = Design Of Journal Bearing
Branch : Mechanical 7C-1
Prepared by: Shah Hitarth M.(150120119171)
Submitted to Prof.:- Dhaval Patel

2. CONTENTS
• Introduction
• Types Of Journal Bearings
• Material Used For Journal Bearings
• Terms Used In Hydrodynamic Journal Bearings
• Bearing Characteristic Number And Bearing
Modulus
• Design Procedure For Journal Bearings

3. INTRODUCTION
In journal bearing sliding action is along the circumference of
circle or an arc of circle and carrying radial loads. [1]

4. TYPES OF JOURNAL
BEARINGS
• According to angle of contact of journal
bearings [2]

5. CONTINUE …..
According to thickness of lubricating
layer [3]

6. HYDRODYNAMIC AND HYDRO STATIC
BEARINGS

7. MATERIAL USED FOR JOURNAL
BEARINGS
1.Babbit metal
•Tin base (Tin 90 %, copper 4.5 %, lead 0.5 % ) and
•Lead base (Lead 84 % Tin 6 %,Antimony 9.5
%copper 0.5)
•Bronze
•Cast iron
•Silver
•Non metallic bearings

8. TERMS USED IN HYDRODYNAMIC JOURNAL
BEARINGS
1.Diametral clearance(c)=D-d
2.Radial clearance(C1)=R-r=(D-d)/2
3.Diametral clearance ratio=
c/d=(D-d)/d
4.Eccentricity is the radial distance between
center of bearing displace center

9. CONTINUE
5.Minimum oil film thickness (ho)assume
ho=c/4
6.Eccentricity ratio(E)=e/C1 =(C1-ho)/c1
7.short bearing (I/d<1) and long bearing(I/d>1)

10. BEARING CHARACTERISTIC NUMBER AND
BEARING MODULUS
Coefficient of friction (f) = φ (ZN/p,
d/c , l/d ) [1] ZN/p is bearing
characteristic number

11. DESIGN PROCEDURE FOR JOURNAL
BEARINGS
There are two methods for journal bearing
design. [4]
1. M. D. Hersey and
2. A. A. Raimondi and J.
Boyd

12. M. D. HERSEY
METHOD
Based on dimensional analysis, applied to an infinitely long bearing.
For given Bearing load (W) ,Journal diameter (d) ,Journal speed (N)
1.Find length by choosing I/d ratio from Table 1.
•Check bearing pressure p=W/Id
•Assume lubricant from Table 2 and check operating temperature
(to)

13. Table 1
[5]

14. Table 2. Absolute viscosity of commonly used lubricating
oil

15. CONTINUE
4. Determine ZN/p and check from Table 1.
5. Assume clearance ratio c/d from Table 1
6. Determine �
7. k is equal to 0.002 for l/d ratio of .75 to 2.8
4. Determine heat generated Qg=FWV watts
• Determine heat dissipated Qd=CA(TB -TA )

16. A. A. RAIMONDI AND J. BOYD
• This method is based on hydrodynamic theory used a
parameter
Raimondi and Boyd based on an iterative technique. For L/d
ratios of 1, 1:2 and 1:4 and for bearing angles of 3600 to 600
extensive design data are available.
Sommerfeld number

17. • Charts have been prepared by Raimondi and Boyd for various design
parameters, in dimensionless form, are plotted with respect to
Sommerfeld number. [6]

18. CONTINUE
• These design parameters are given by Raimondi
and Boyd
1.Minimum film thickness (ho/c)
2.Friction coefficient f
3.Flow ratio Qs/Q
4.Maximum film pressure ratio p/pmax
5.Minimum film thickness position θo

19. REFRENCES
[1]. A text book of machine design by R.S. Khurmi and J.S. Gupta
reprint in 2011
[2]. http://www.mdpi.com/2075-4442/3/3/569/htm (accessed on
08/1/017)
[3]. http://www.bearingsensor.com/sleeve%20bearing
%20lubrication.html
[4]. http://nptel.ac.in/courses/112102015/30
[5] http://nptel.ac.in/courses/112102015/20
[6].http://www.substech.com/dokuwiki/doku.php?
id=hydrodynamic_journ al_bearing