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