Magnetorheological Fluid Technology

228 Magnetorheological Fluid Technology: Applications in Vehicle Systems

mode of MR uid. The torque is generated from rotary motion between the

housing and the electromagnetic disk. The equation of the generated torque

of the MR fan clutch is mathematically given by

T A R T

R t

R g R f

g

R g f

g

R hf

g

y

o y

o v i

h

o v

h

o

v

4

( )

( ) 4

2

2 4 4

2 4 2 3

{ }

= τ × × +

= π τ +

π η + −

+

π η +

+

π η

η

(8.6)

where R

o

and R

i

are the outer and inner radius of the electromagnetic disk,

and A is the contact area between the electromagnetic disk and MR uid. h is

Output Shaft

Coil

MR Fluid

Input Shaft

FIGURE 8.4

Schematic conguration of the proposed MR fan clutch.

w

h

t

dh

g

v

g

h

R

i

R

o

FIGURE ...