Subaru XT 1988 Service Manual page 848

4-3
STEERING SYSTEM
MECHANISM AND FUNCTION
VGR (Variable Gear Ratio)
Gearbox
The variable gear ratio (VG R) gearbox is adopted on some
manual steering models to reduce steering effort when making
a full turn. This VGR gearbox adopts different rack tooth
shapes between the straight-ahead position and the fully
turned position. This varies the pitch circle diameter of the
pinion which engages with the rack teeth so as to provide a
solid steering feel when steering in the straight ahead position
and a light steering feel during turns.
~
~
Cl
c:
'0,
c:
(II
~
u
Fig. 1
I
Variable Gear Ratio (VGR) type
I
30
20
/
10
Q
-10
Rack stroke
Straight
Full turning
I
Constant Gear Ratio (CGR) type
I
~
30
~
20
~
10
' g .
0
f - - - - - - - - - - - - 1
~--1O
U
Straight
Rack stroke
Full turning
L4-223
The gear ratio is approx. 20 in the straight ahead position and
approx. 25 in the full turn position.
2
I