7Speed Lepelletier
Clutch schedule for a sevenspeed Lepelletier transmission
Libraries:
Simscape /
Driveline /
Transmissions
Description
The 7–Speed Lepelletier block consists of one planetary gear set, one Ravigneaux gear set, and six disk friction clutches. The transmission base shaft connects to the ring gear of the planetary gear set. The follower shaft connects to the ring gear of the Ravigneaux gear set. Three of the clutches control the powerflow paths between the planetary and Ravigneaux gear sets. The other three clutches serve as brakes, grounding various gears of the Ravigneaux set to the transmission housing.
This diagram shows a sevenspeed Lepelletier transmission. The labels for the gear components are superimposed on the input and output gears. The table lists the gear and clutch components that are labeled in the diagram.
Label  Component 

P.G.  Planetary gear 
R.G.  Ravigneaux gear 
R  Ring gear 
C  Planet gear carrier 
S  Sun gear 
SL  Large sun gear 
SS  Small sun gear 
A–C  Forward clutches that control the powerflow path 
D–F  Forward, braking clutches 
Drive Ratios, Clutch Schedule, and Power Flow
The drive ratio between the transmission input and output shafts follows from the elementary gear ratios specified for the gear blocks. The elementary gear ratios are
$${g}_{1}=\frac{{N}_{PR}}{{N}_{PS}},$$
$${g}_{2}=\frac{{N}_{RR}}{{N}_{RSL}},$$
and
$${g}_{3}=\frac{{N}_{RR}}{{N}_{RSS}},$$
where:
N_{PR} is the number of teeth in the planetary ring gear.
N_{PS} is the number of teeth in the planetary sun gear.
N_{RR} is the number of teeth in the Ravigneaux ring gear.
N_{RSL} is the number of teeth in the Ravigneaux large sun gear.
N_{RSS} is the number of teeth in the Ravigneaux small sun gear.
The table shows the clutch schedule, driveratio expressions, driveratio default values, and the powerflow diagrams for each gear of the 7Speed Lepelletier block.
The letters in the clutch schedule columns denote the brakes and clutches. A value
of 1
denotes a locked state and a value of 0
an unlocked state. The clutch schedule generates these signals based on the Gear
port input signal. The signals are scaled through a Gain block and used as actuation
inputs in the clutch blocks.
The powerflow diagrams show the powerflow paths between input and output shafts for each gear setting. Power flow is shown in orange. Connections to the transmission housing (a mechanical ground) are shown in black.
Gear  Clutch Schedule  Drive Ratio Equation  Default Ratio  Power Flow  

A  B  C  D  E  F  
7  0  1  0  0  1  1  $$\frac{{g}_{2}}{1+{g}_{2}}$$  0.70 

6  1  1  0  0  0  1  $$\frac{{g}_{2}\left(1+{g}_{1}\right)}{{g}_{2}\left(1+{g}_{1}\right)+1}$$  0.86 

5  1  1  1  0  0  0  $$1$$  1 

4  0  1  1  0  0  1  $$\frac{{g}_{3}\left(1+{g}_{1}\right)}{{g}_{3}\left(1+{g}_{1}\right)1}$$  1.17 

3  1  0  1  0  0  1  $$\frac{1+{g}_{1}}{{g}_{1}}$$  1.63 

2  0  0  1  0  1  1  $$\frac{\left(1+{g}_{1}\right)\left({g}_{3}+{g}_{2}\right)}{{g}_{1}\left(1+{g}_{2}\right)}$$  2.43 

1  0  0  1  1  0  1  $$\frac{{g}_{3}\left(1+{g}_{1}\right)}{{g}_{1}}$$  4.31 

R  1  0  0  1  0  1  $$\frac{{g}_{2}\left(1+{g}_{1}\right)}{{g}_{1}}$$  3.82 

Examples
Ports
Input
Conserving
Parameters
Extended Capabilities
Version History
Introduced in R2015a
See Also
4Speed CRCR  4Speed Ravigneaux  6Speed Lepelletier  8Speed  9Speed  10Speed