Environmental Engineering Reference
In-Depth Information
The governing equation for an epicyclic gear in terms of the basic ratio and
gear angular speeds can be written as shown in (4.3):
w
s
þ
k
w
r
ð
k
þ
1
Þ
w
c
¼
0
ð
4
:
3
Þ
In Table 4.2, the relationship noted in (4.3) is used to explain the behaviour of
selected two ports when the third port is held grounded. This is the single input,
single output case. When the third port is released, the behaviour is governed by
(4.3). The Lexus GS450h, for example, uses a separate planetary gear as the means
to ratio shift the traction motor MG1 in the eCVT.
Table 4.2 Epicyclic gear input-output relationships
Configuration
Direction of
speed
Grounded
port
Input
port
Output
port
In
Reversed
Carrier
Ring
Sun
R
C
S
w
c
=0
w
r
w
s
=
k
w
r
Out
In
Normal
Sun
Ring
Carrier
R
C
S
w
s
=0
w
r
w
c
=[
k
/(
k
+ 1)]
w
r
Out
Normal
Ring
Carrier
Sun
R
C
S
w
r
=0
W
c
W
s
=(
k
+1)
c
In
Out
Normal
Sun
Carrier
Ring
Out
R
C
S
w
s
=0
w
c
w
r
=[(
k
+ 1)/
k
]
w
c
In
Normal
Ring
Sun
Carrier
R
C
S
Out
w
r
=0
w
s
w
c
= 1/(
k
+1)
w
s
In
Reversed
Carrier
Sun
Ring
Out
R
C
S
w
c
=0
w
s
w
r
=(
1/
k
)
w
s
In
