This technical paper was jointly written by ProSIM & AVTEC. ABAQUS / Fesafe / SIMPACK were the softwares used for this research!

1. 25/01/16 www.pro-sim.com
Design & Development of an
Integrated Transmission System
A case study of successful collaborative engineering between
AVTEC & ProSIM R&D Pvt Ltd

2. 2
PREAMBLE
 Issues involved in development of a Integrated
transmission system for AWD
 Optimizing the product (material, geometry for
needed performance)
 Success of collaborative engineering for product
innovation and NPD
 Optimizing the investments and optimization of
RoI are discussed.

3. ProSIM
- A simulation technology based collaborative
R&D company
- Inter disciplinary team of experts
- Design –materials - Manufacturing-
performance
- Multi-physics simulation capabilities
25/01/16 www.pro-sim.com

4. ProSIM
- We assist customers in
- New product development
- Innovation / R&D projects
- VA / VE
- Failure analysis
25/01/16 www.pro-sim.com

5. 5
Design of Gearbox
Product design and development
 An integrated transmission for vehicle having 5 forward speeds & 1 reverse speed
within the specified torque & rpm range.
4th
Gear
3rd Gear
2nd Gear
1st Gear
Reverse Gear
5th Gear Front Output
Rear Output

6. Workflow
- Study the customer requirements
- Design specifications and conceptualisation
- Engineering design
- Digital mock up
- CAE and FEM analysis
- Durability analysis
- MBD model (flexible model)
- NVH Analysis
- Optimisation
- Physical prototype
- Testing
- Design fine tune
- Control drawing release
25/01/16 www.pro-sim.com

7. Design Validation of an Integrated Transmission
System
Automotive Noise & Vibration Congress, Pune

8. • Introduction
____________________________________________________
• Integrated Transmission & Transfer Case
• Features
____________________________________________________
• Conceptualizing the Product
• Mass addition for Shift-ability
• Testing on Acoustic Chamber

9. 9
Introduction 7-Feb-16
 OEM’s demands higher performance, NVH, safety & quality are increasing
day by day.

10. 10
7-Feb-16
 It is now necessary to utilize company’s investment in design stage gate
process qualification, virtual prototyping & physical prototyping.
 Development of superior design is mandatory as technology, methods,
guidelines & tools are available on finger tips.
 Design is signed off for performance, quality, safety & cost so that a
higher upgraded version of the model can be achieved after passing all the
stage gates.
Business Case Feasibility
Schematic
Design
Design
Development
Pre
Construction
Construction
Introduction

11. 11
Integrated Transmission & Transfer Case7-Feb-16
5 speed manual transmission Motor shift transfer case

12. 12
Cut section 7-Feb-16

13. 13
7-Feb-16
HIGH GEAR PAIR
GEAR RATIO: 1.205
LOW GEAR PAIR
GEAR RATIO: 2.127
4TH GEAR PAIR
GEAR RATIO: 1.000
3RD GEAR PAIR
GEAR RATIO: 1.3642
2ND GEAR PAIR
GEAR RATIO: 2.260
1ST GEAR PAIR
GEAR RATIO: 3.737
REVERSE GEAR PAIR
GEAR RATIO: 3.4028
5TH GEAR PAIR
GEAR RATIO:
0.7757
TRANSMISSION
TRANSFER CASE
Gear Train

14. 14
Features 7-Feb-16
 This transmission is designed for a vehicle which is on-road luxurious SUV
& at the same time can run on ice covered roads too.
 Demands speed & torque at different times.
 The unique feature is that transfer case is directly mounted on rear cover of
transmission for compactness.
 It compliment design of engine, axle, propeller shaft & tunnel of vehicle
very well.
 All the designed parts were gone through design stages such as
DFMEA/PFMEA.

15. 15
7-Feb-16
 All the parts of the transmission are built to sustain a temperature range of
-30 degree Celsius to 50 degree Celsius.
 Material selection for all parts is done for adverse condition and considering
variations in temperature.
 The B10 life for all the parts qualifies as per demanded.
 Effect of all torque transfer parts such as gear, shafts, synchronizers,
bearings were analysed with respect to the manufacturing accuracies.
 All the design were checked for serviceability, assembly, quality & cost
before signing off with customer.
Features continues…

16. Conceptualizing the Product
2/7/2016

17. Initial Study & Data Receipt

18. 13.69° (~14 °)
Shift-ability

19. Shifting Testing 2/7/2016

20. 07/02/2016
S.no. % of total time Front Axle (% of total torque) Rear Axle (% of total torque)
1 10% 100% 100%
2 30% 120% 80%
3 30% 80% 120%
4 10% 140% 60%
5 10% 60% 140%
6 5% 200% 0%
7 5% 0% 200%
Load Cases for testing

21. Modelling and Simulation
- ABAQUS is used for finite element analysis
- FESAFE is used for fatigue damage and
durability assessment
- SIMPACK is used for flexible multi-body
dynamic simulation (order analysis, NVH, etc)
25/01/16 www.pro-sim.com

22. 2
2
Modeling andSimulation
Multi-body dynamic Simulation
Components in the main model
-Flexible housing
-Flexible shafts
-Gear wheels
-Synchronizer

23. Components:
Flexible bodies Figure: Flexible Body generation in SIMPACK – Steps followed
Drive trainmodeling

24. Components:
Gear
1. Normal Module
2. Normal Pressure Angle
3. Helix Angle
4. Number of Teeth
5. Addendum DiameterHeightCoefficient
6.Deddendum DiameterHeightCoefficient
7. Shift Factor
8. Flank Width
Drive trainmodeling

25. Calculation accordance with
DIN 3990-1:1987-12
Gear pair Parameters Analytical calculation
Drive trainmodeling

26. Bearings
Ball bearings
Needle roller bearings
Nonlinear bearing stiffness value
Drive trainmodeling

27. Speed engagement
Load case
Figure: Example load case as 1st gear engaged
Input torque
Reverse torque
Drive trainmodeling

28. Drive trainMain model
Topology
Topology diagrams ease the
understandability of the
model
FE43 - Force Element Representing Bolting
FE225 - Force element representing gear pair
DOF - Degrees of Freedom
FE93 - Force Element Representing input
torque

29. MBDResult
Using MBD Bearing forces
The Bearing reaction forces are considered as an input for
Structural analysis of housing components as shown in
the figure.
By FFT (Fast Fourier Transform) converted bearing loads
it could be possible to conduct housing acoustic analysis
in FE.
Figure: Bearing reaction forces

30. Vibration analysis of gearbox
Methodology and Inputs
• Flexible gear shafts
• Switchable gears
• Bearings (Non linear stiffness and damping values)
• Synchro bodies as dummy bodies
• Rigid gearwheels with detailed macro- and micro-geometry
• Gearwheels with material data
• Gear pair contact
Figure: Nonlinear bearing stiffness value
Figure: Gear tooth modification

31. Vibration analysis of gearbox
Sensors at Probe location
on housing to extract accelerations
Figure shows the sensors location on the
housing components
The resultant housing acceleration in all
direction captured at sensors locations.
Probe locations

32. MBDResult
Vibrationanalysisofgearbox
RMSvelocity atprobe-2

33. MBDResult
Vibrationanalysisofgearbox
Accelerationatprobe- 2

34. MBDResult
Vibrationanalysisofgearbox
Campbell plotforaccelerationatprobe- 2 Housing Acceleration
From the figure shows critical RPM for a particular order(3rd Gear pair and 2nd harmonic of
TC Gear pair) of vibration indicating the source of high vibration in the system

35. Observation
Vibration analysis of gearbox
1. In order analysis the RPM is increased from 0 to maximum, with a constant
acceleration. This is done in order to see at what RPM the system has maximum
amplitude of vibration
2. The maximum amplitude of vibration occurs because of the interaction of natural
frequencies of vibration and forcing frequencies (teeth meshing frequency of any one
of the gear pairs).
3. The natural frequencies also considerably depends on the mounting locations of the
housing. The critical RPM may change if the mounting locations and stiffness values
are varied

36. Assembly

37. Description of the transmission assembly

38. Description of the differentialgear system

39. Boundarycondition
The transmission assembly is fixed in bearing locations (highlighted - six location), The
shafts are allowed to rotate along the shaft axis (rotation along X– direction).

40. Results – Transmission Assembly

41. Results – Transmission Assembly

42. Results – Differentialgear Assembly

43. Durability
Fatigue analysis is carried out taking the results of non linear static FE results.
Appropriate fatigue material properties are assigned for all the components from the
material library of the software and a cyclic half sine wave load (zero to max) is
applied to predict the fatigue life of the system.

44. Fatigue lifeof Transmission assembly

45. Minimum Fatigue life (crack initiation
life) observed in the Transfer case
assembly is as shown.
Fatigue lifeof transfer case

46. NVH
The air meshing is considered as a cylinder of 350 mm radius from the Transmission axis

47. Noise Probing location

48. Noise predicted in simulation

49. Noise Comparison at probe location-8

50. Conclusions
- A integrated transmission system for SUV with AWD is
developed
- Static Stress, modal/ harmonic analysis, contact stress
analysis carried out using ABAQUS.
- Customer desired fatigue life and noise levels have been
achieved by simulation based studies (using Abaqus, Fesafe
and SIMPACK)
- Physical testing & prototyping time &effort is reduced.
- Using good collaborative practices between ProSIM and
AVTEC, a new transmission system was developed in a short
time, with minimal cost.
25/01/16 www.pro-sim.com