January 12, 1999

Coupling with a lockup mechanism, "AXC-II (Axial Piston Pump Coupling)", which Fuji Univance Corporation developed was adapted to the DAIHATSU Atrai.

 

A coupling with lockup mechanism, "AXC-II (Axial Piston Pump Coupling Two)", which Fuji Univance Corporation developed was adapted for the full-time 4WD new model Atrai which was released onto the market by Daihatsu Motor Co., Ltd. on January 6, 1999.

 The "AXC-II" is a device which idealistically splits the transfer torque to front and rear wheels of 4WD vehicles, thus increasing driveability in situations where wheels are normally apt to slip.  In driving conditions whereby the rear wheels are normally apt to slip such as icy, snowy or muddy roads the transfer torque is transferred to the front wheels.  This feature ensures excellent driveability. 

With this technology as a whole, less expensive, smaller and lighter vehicles can be achieved because full-time 4WD is now possible, rendering the front and rear wheels in a rigid condition without a change mechanism. 

AXC-II for the DAIHATSU Atrai is assembled within the transfer unit.  An initial high transfer torque was added to the conventional system which prevents the rear of the vehicle from swinging in slippery road conditions.  The use of aluminum forging instead of the conventional steel type enabled a 1kg lighter housing. 

The AXC is based on an axial piston pump which operates in the direction of rotation and consists of a rotor, a piston, a cam housing and rotary valve with lockup mechanism.  The basic principle is that transfer torque occurs in a system by utilizing the resistance developed when the oil discharged from the cylinder passes through the orifice.  When the torque reaches the set point a mechanism is provided which makes the front and rear wheels become rigid as the orifice closes (Auto Lockup Mechanism). 

When a speed difference between the front and rear wheels is small, more drive force is transferred to the rear two wheels and less drive force is applied to the front wheels which allows increase in fuel economy and reduction of wear of tires.

When a speed difference becomes large in a condition like icy, snowy or muddy road, more drive force is transferred to the front wheels and automatically lockup when the drive force (speed difference) reaches the set point, rendering the front and rear wheels in direct drive, which enables running through performance similar to rigid 4WD vehicles. 

If you have any inquiries, please contact Mr. Hirohisa Maki at Fuji Univance Corporation, Phone #(053)576-1314, Facsimile #(053)576-1990. 

FUJI UNIVANCE CORPORATION
2418 Washizu, Kosai-City, Shizuoka 431-0494  Japan