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General The steering gear ratio will be changed in accordance with the vehicle speed . VGRS (Variable Gear Ratio Steering) System. a. a - . a + . Low Ratio (Quick). High Ratio (Slow). Vehicle speed low. Vehicle speed high. VGRS System. Major Difference from ’05 LX470. DLC3.
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General The steering gear ratio will be changed in accordance with the vehicle speed VGRS (Variable Gear Ratio Steering) System a a - a + Low Ratio (Quick) High Ratio (Slow) Vehicle speed low Vehicle speed high
VGRS System • Major Difference from ’05 LX470
DLC3 VGRS System • System Diagram Steering Angle Sensor VGRS Actuator VGRS ECU Serial Communication Lock Mechanism Spiral Cable Motor Skid Control ECU CAN Resolver Temp. Sensor Engine ECU (ECM) CAN BEAN Serial Communication Gateway ECU EPS ECU Combination Meter
VGRS System • Steering Gear Ratio Confidential Slow 19 VGRS system not operates 17 Steering Gear Ratio 15 Lock to Lock : 3.2 Quick 100 (62) 200 (124) Km/h (mile) Lock to Lock : 2.7 Vehicle Speed
VGRS System • System Operation Steering Angle Sensor VGRS Actuator Motor Rack & Pinion Gear Control Signal (Target Operating Angle) VGRS ECU Steering Angle Map Calculate actuator target operating angle Actuator Operating Angle Skid Control ECU Vehicle Speed Vehicle Speed
VGRS System • System Operation • VGRS ECU adds the supplemental assist with steering speed to reduce delay of vehicle response Normal Operation Actuator Output Assist
VGRS System • VGRS Actuator VGRS Actuator Spiral Cable Steering Wheel Lock Mechanism Motor Rack & Pinion VGRS Actuator Assembly Reduction Mechanism
VGRS System • Spiral Cable • Flexible flat cable is used Spiral Cable (Flexile Flat Cable) VGRS ECU Control Signal, Power Source Rotational angle and rotational direction of the motor Motor
VGRS System • Lock Mechanism • Locks the motor shaft Lock Mechanism A – A Cross Section Lock Holder (Motor Shaft) Solenoid A A Motor Shaft Return Spring Lock Lever (Housing)
VGRS System • Lock Mechanism • Lock / unlock operation Solenoid “ON” Solenoid “OFF” Unlock Lock
VGRS System • Motor • A compact high-output low-noise brush-less motor Rotation Angle Sensor (Resolver) Brush-less Motor Motor Shaft Magnet Coil Reduction Mechanism
VGRS System • Reduction Mechanism • The strain wave gearing type reduction mechanism Motor Stator Gear Stator Gear Flexible Gear Wave Generator Driven Gear Flexible Gear Wave Generator Driven Gear Output Shaft
VGRS System • Reduction Mechanism • Components Stator Gear (input) Driven Gear (output) Wave Generator (input) Flexible Gear Steering Wheel Rack & Pinion
VGRS System • Reduction Mechanism • Number of teeth Stator Gear (input) Driven Gear (output) Wave Generator (input) Flexible Gear 100 100 102 The difference of number of teeth
VGRS System • Reduction Mechanism • Construction Stator Gear Flexible Gear Wave Generator Meshing Ball Bearing is between flexible gear and wave generator Not meshing View from stator gear side (Steering wheel side)
VGRS System • Reduction Mechanism • Operation of strain wave gearing Motor Shaft Flexible Gear (100 teeth) Wave Generator Stator Gear (102 teeth) Ball Bearing (Between flexible gear and wave generator) View from stator gear side (Steering wheel side)
VGRS System • Reduction Mechanism • Operation of strain wave gearing Stator gear fixed View from stator gear side (Steering wheel side)
Click! Movie VGRS System • Reduction Mechanism • Operation of strain wave gearing Flexible Gear (100 teeth) Stator Gear (102 teeth) Shifts by 2 teeth Wave generator makes one turn Driven Gear (100 teeth)
VGRS System • Reduction Mechanism • Reduction gear ratio Flexible gear rotates one turn Wave generator (motor) rotates 50 turns Gear Ratio : 50 1 Flexible Gear Motor
Click! Movie VGRS System • Operation • Vehicle speed is low (quick ratio) Add steering angle M
Click! Movie VGRS System • Operation • Vehicle speed is mid. (normal ratio) M No assist
Click! Movie VGRS System • Operation • Vehicle speed is high (slow ratio) M Reduces steering angle
VGRS System • Warning Message • VGRS warning message for the system malfunction Warning Message
VGRS System • Diagnosis • 29 DTCs for VGRS system
VGRS System • Diagnosis • 29 DTCs for VGRS system
Initialization and Calibration VGRS System