New Traction Drive Pairing withInner Spherical Rotor for Automobile

Usage

Depart of Mechanical Design, Pusan National Univ. South Korea.

Researcher: Ilkeun KuProfessor: Nogill Park

Layout

1. Driving / driven rotor

2. Traction ball assembly

3. Pressure device

4. Ratio changer

- Basic components

Operation principle

- ISCVT assemnly

Operation principle

- Pressure device

1 11

1 1

/

cos tan costhF T r

N

/

tan tant i i

th

F T rF

Operation principle

- Traction ball assembly components

1. One pair of countor rotor

2. Two bearings

3. Countor rotor shaft

4. Countor rotor housing

5. Connector between CRA and RC

Operation principle

- Ratio changer and speed ratio

2 4

1 3

h h

h h

Numerical investigation

▪ Max. power 110 kW / 6,000 RPM

▪ Max. torque 194 N·m / 4,500 RPM

▪ Overall speed ratio 0.09~0.37

▪ Driving / driven rotor diameter range

100 ~ 200 mm

▪ Radius of traction ball range 10~50 mm

▪ height of traction ball pivot range 50 ~ 100 mm

▪ Preloading thrust forces range 0.1 ~ 500 N

▪ Cam lead angle range 0.1 ~ 50°

- Design specification for the passenger car

Numerical investigation

Kinematic analysis- Calculate traction ball angle range

Kinetic analysis- Direction vector declaration- Torque equilibrium Equations- Hertzian contact theory- Life time- Transmission efficiency

Simulation results

Simulation start

Input design parameter

End program

- Flow chart

Numerical investigation

Optimal design variables

▪ Radius of driving / driven rotor 125 mm

▪ Radius of traction ball 43.3 mm

▪ Height of traction ball pivot 52 mm

▪ Cam lead angle 36°

▪ Preloading thrust force 220 N

Transmission performances

▪ Transmission efficiency 93 %

▪ Ratio changer work 263 joul

▪ Life time 10,800 hour

▪ Maximum shear stress 552 MPa

▪ Gradeability 20°

- Simulation results

Stress analysis

-Driving rotor, traction ball,

- Frame and bearing housing

Performance analysis

Transmission efficiency (%)

2 2

1 1

T

T

Performance analysis

Maximum shear stress (MPa)

Driving rotor Driven rotor

1sd

sd

VpV

<<<<<<<<<<<<<<<<<<<<<<<<<<<<

<<<<<<<<<<<<<< ( , )rp C 1

sd

r

VC

V

<<<<<<<<<<<<<<

<<<<<<<<<<<<<<

Performance analysis

Life time (Hour)

Driving rotor Driven rotor

Performance analysis

Ratio changer work (Joul)

max 1 2 max min( ) ( )rcW N N r

Performance analysis

Gradeability (Degree)

21sin

2thrust air area

tire

F C VC

Wg Wg

Capacity expantion

Transmission efficiency (%)

Capacity expansion

Maximum shear stress (MPa)

Capacity expansion

Life time (Hour)

Comparison with toroidal CVT

Performance analysis

Comparison with toroidal CVT

Performance analysis

Comparison with toroidal CVT

Performance

Comparison with toroidal CVT

Power density

[ / ]Power

PowerDensity kWVolume

2

11019.3 /

220150

4

ISCVT kW

2

1108.6 /

260240

4

TCVT kW

Apply to the automobile

Conclusion

Introduce a new traction drive ISCVT.

Perform kinematic / kinetic analysis and derive the speed ratio.

Numerical investigation and conceptual design on the basis of simulation results. ▪ CAD and stress analysis

Apply to the 110 kW automobile and evaluate its performances. ▪ Transimssion efficiency, ▪ Maximum shear stress ▪ Life time ▪ Gradeability ▪ Ratio changer work

Comparison with toroidal CVT and the results show the better performances.