DESCRIPTION OF CONSTRUCTION AND OPERATION

HYBRID LIMITED SLIP DIFFERENTIAL

• Hybrid LSD consists of torque sensing type helical gear and wheel speed sensing type viscous coupling unit.
  
• The number of the components is reduced in the helical part (torque-sensing part), because in this location both the driving force transfer and the limited slip differential torque generation take place.
  
• The viscous coupling (speed differential-linked part) realizes the stable driving force and outstanding dynamic performance at any drive conditions.
  
• On-road performance, start-up performance on low-µ road, steering stability, and straight-line stability have been much improved than those of mechanical LSD.
  
• Excellent LSD response, and it is easy to control vehicle’s posture via accelerator operation
  
• The torque bias ratio, which shows volume of the limited slip differential torque, is higher on the drive side than the engine brake side. The optimised viscous coupling torque ensures the combination with ABS.
  

CONSTRUCTION DIAGRAM

HYBRID LSD OPERATION MECHANISM

1. Because of road condition change or a sharp cornering, when the loads on the right and left wheels become unbalanced, the driving torque difference is caused between the side gears A and B. The side gears A and B are engaged via a long pinion and a short pinion. The gears affect each other and the engagement reaction force is generated between the side gear A and the short pinion and between the side gear B and the short pinion. With the axial component of this engagement reaction force, the side gears A and B receive the force in the direction of spreading respectively. This force presses the side gears A and B against the corresponding thrust washer to generate the friction. Also, with the radial component of the engagement reaction force, the long pinion and short pinion receive the force in the direction of pressing against the differential case. This force generates a large friction force between the long pinion/short pinion and differential case. In addition, in the engagement areas of four gearwheels (pinions), the engagement reaction force is generated and thus the friction occurs on the surfaces of teeth. This friction consequently causes local friction torque depending on the amount of the input driving torque of the differential case, generating the limited slip differential torque proportional to the input torque.
   
2. When one wheel has no contact with the earth (one wheel slipping), there will be almost no driving torque on the slipping wheel. The side gear on the slipping wheel rotates independently, because no engagement reaction force is generated. Therefore, the rotation speed between side gears A and B becomes higher to generate the limited slip differential force in the viscous coupling. This transfers the torque to the side gear on the wheel having contact with the earth.
   
3. When the steering wheel is turned slowly at cornering, small torque is applied to the rear differential. The friction force described in the item 1 is also small, and a smooth cornering can be achieved as with the normal differential.
   
4. When the axle rotates in the same speed on the right and left ends (the vehicle in straight-ahead position), the gears and differential case rotate together as with the normal differential.
   

REAR DIFFERENTIAL LOCK SYSTEM

• Locks the right and left wheels completely to facilitate the escape from running off, rocky road, or snowy road.
  
• Adopts the compact structure with diaphragm, and highly reliable with regard to stone chips or freezing.
  
• Adopts the electronic control system. For security and protection of the lock mechanism, the system refuses the changeover to the differential lock at the speed of 12 km/h or more even if the differential lock switch is turned ON. When the vehicle speed drops to 6 km/h or less, the differential is locked (however, the changeover can be carried out at less than 12 km/h). The changeover from Locked to Free can be carried out at the speed of 12 km/h or more.
  
• Differential lock changeover is carried out by means of a rear differential lock switch which is located on the driver’s side instrument panel.
  

CONSTRUCTION DIAGRAM

REAR DIFFERENTIAL LOCK SYSTEM CIRCUIT DIAGRAM

REAR DIFFERENTIAL LOCK SYSTEM OPERATION MECHANISM