Présentation PowerPoint - EMM Mechatronics

Optimisation énergétique d'un véhicule électrique par la mise en œuvre d'un moteur-roue et des systèmes « by wire » E Asano NTN Japan EV project manager H Lénon NTN-SNR Europe Innovation Manager

Employees Turnover for 2010

19172

5128

4.8 billion euros

1,3 billion Euros

Head office Osaka Japan

R&D Europe Center Mechatronic reference center

N°1 in France

N°1 in Automotive industry N°3 worldwild Bearings Plummer block Linear modules Mechatronic systems and sensors …

Groupe SNR-NTN

NTN group presentation

Car frictions overview Energy consumption due to mechanical frictions

Steering

Engine Transmission Breaks Bearings

Engine – In Wheel Motor

The IWM system, encompasses various mechatronical functions in a global approach of the vehicle: rotation of the wheel motor reducer inverter brakes sensors and associated control laws.

Engine - In Wheel Motor

Direct drive type Tire

Motor

With reducer type - NTN

Reducer

Bearing

With reducer

Cost

★☆☆ ( high)

★★★ (Low)

Efficiency

★★★

★★☆

Energy consumption

★★☆

★★☆

Unsprung mass

Bearing

Tire

Direct drive ★☆☆ (Heavy)

Motor

★★★ (Light)

Engine – In Wheel Motor

Radial Synchronous Internal Permanent Magnet Stator and rotor were designed by NTN through modeling of magnetic fields and stress analysis, : reduced electrical power losses reduced temperature reduced axial size (compact coil) possible air cooled system even with high speed 2 possible power ranges : 4kW for small urban cars (commuter): 50 km/h to 75 km/h 30 kW “A, B Segment cars “: 150 km/h

Example of axial motor

Engine – In Wheel Motor Cycloïd reducer

Output shaft （Conecting internal pin）

Internal gear External gear Internal pin

Input shaft Ratio of 1/11 : Speed : engine input speed 15,000 rpm wheel speed 1350 rpm Torque input motor torque very small : 45 Nm output torque : 500 Nm Mass and energy are greatly reduced.

Engine – In Wheel Motor Cycloïd reducer

Reduction ratio

1

Direct drive

1

2

Planetary gear

4

Cycloïd gear - NTN

11

3

Weight of In-wheel motor

Reducer type

Optimum region

1

2 Reduction ratio

3

8

Steer by wire

Steering

Steer by wire Steering system with mechanical column

NTN by wire steering system

Steering reaction force actuator

Steering actuator

Freedom of design : - right and left drive without big mechanical modification - no more problem of limit column angle - more space Security : no more problem in case of frontal crash Energy saving …

Steer by wire Reaction force actuator

Mechanical Stopper of Steering Wheel

Steering Wheel

Torque Damper

Motor

Gear Reducer

Encoder

Sensor

A common shaft for all the functions : the size and weight are reduced a motor : generate a resistive torque a torque damper : a viscosity fluid fill the space between the output shaft and housing a gear reducer a mechanical stopper : to limit the number of rotations an encoder & sensor : to measure the angular position of the steering wheel

Steer by wire Steering actuator

Switching Shaft

Primary Motor

Ball Spline

Screw（For Adjusting Toe Angle） Secondary Motor Ball Screw NTN steering actuator particularities : - 2 motors : primary & secondary guarantee a high level of security (redundancy) - 2 ball screws : one to orientate simultaneously the 2 wheels a ball spline to adjust the angle between right and left wheel Ball screw reduce friction comparing to rack rail

Linear Solenoid

Steer by wire Steering actuator

Theoretical approach Vehicle : - speed = 60 km/h - rotation on a 50m radius circle F : lateral force W : tire vertical force Slipping conditions if F/W > µ With a road surface friction coefficient µ = 0.7 slipping condition on left wheel and right wheel for a + and - 2° toe angle

The lateral force increase with the toe angle in clockwise (CW) direction and counterclockwise (CCW) : • 4 kN variation for a toe angle variation of 4° • Energy consumption increase with the toe angle :

Brake by wire

Electromechanical Brake (EMB)

Caliper

Brake Pad

84.5㎜

Brake Disk

Linear motion device (Planetary roller screw)

Motor

Electromechanical Brake (EMB)

1. Compact and light weight : minimize unsprung mass and energy consumption High load conversion rate by small screw lead → omission or simplification of reducer , downsizing of actuator Arrangement of linear motion device and motor in parallel → shortening the axial length of unit Simple system – global weight reduction → no ABS actuator (pump, solenoid), master cylinder, pipes, etc… 2. Reduction of pad/disk friction → caliper position/brake disk controled by force sensing → reduction of friction 3. Improvement of vibration durability fretting wear is prevented by giving radial preload

Conclusions

NTN system

Advantages mass -25%

In-wheel motor system

(comparing to central motor EV car)

Freedom in design

Electric mechanical brake system

Steering system for steer-by-wire

size -50% (comparing to existing EMB)

Less friction safety efficiency +25% (comparing to mechanical column )

Less tire slipping

NTN-SNR promotes in Europe NTN technologies for Electrical Vehicle NTN Technologies for electrical drive In wheel motor (4kW and 30 kW) with integrated reducer One Motor Type (60 kW) And 2 speeds automatic transmission

NTN demonstration vehicles to provide support to technology

Q’mo : 4 in Wheel Motors and 4 independent steerings

Commuter 2 : 2 rear In Wheel Motors (IWM) of 4 kW . Maximum speed : 60km/h

Commuter 3 : 2 rear In Wheel Motors (IWM) of 4 kW, Maximum speed : 75 km/h