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Positraction Units, don't get stuck again!
We offer a wide selection of positractions to meet your specific application, why you need a positraction unit, when your vehicle is negotiating a corner, the outside
wheel has to travel a grater distance than the inside wheel. Therefore, the outside
wheel must turn faster than the inside wheel. The differential is the device within
the axle assembly which, in addition to transmitting the power to each axle shaft/wheel,
allows one wheel to turn at a different speed than the other.
There are many designs of Differentials including:
- Conventional or Open
- Limited Slip
- Automatic Locking
- Manual Locking
Conventional differential uses two side
gears inside the differential case. Each gear is splinted to accept an axle
shaft. These side gears are in turn driven by a set of spider gears. The spider
gears, also inside the differential case, ride on a shaft which is pinned into
the differential case and through which all the power is transmitted. The case
is driven by the ring gear which is bolted fast to the case. The conventional
differential is fitted as standard equipment on most vehicles.
On paved roads this system is very successful,
giving predictable handling, even tire wear and requiring very little maintenance.
However, in off road situations where traction surfaces vary greatly, this type of
differential has a major limitation. When one wheel has greater traction than the
other, all the power will be directed to the wheel with the least traction.
Limited slip differentials (LSD's) come
in a variety of designs. Most use friction plates, cones and/or gears to reduce slippage
between each of the tires. these units have a dual power path from the differential
case to the axle shafts. some power is transmitted through the spider gears to the
side gears in the conventional manner. The remainder is transmitted by friction between
the differential case and the clutch plates and the side gears.
Automatic locking differentials transmit
power to each wheel through a pair of dog clutches. Differential action, such
as when cornering is provided by automatically disengaging the appropriate clutch
when one wheel rotates faster than the other. This results in differential action
which occurs in ratcheting stages rather than being smooth and progressive.
Power received by the differential is automatically directed to the wheel with
greater traction. T
Manually lockable differentials use a conventional
differential in conjunction with a mechanical locking device which can be operated
at the drivers's discretion. when locked, both axles will then turn at the same
speed irrespective of the road surface. When it is unlocked, the differential functions
as a conventional differential giving predictable handling, long service life and
no increase in tire wear.
The Electric or Air Locker
unit incorporates its activating mechanism totally inside the differential center.
This avoids the need to have complicated piston arrangements hanging off the axle
housing. Locking action is controlled by the drive with a push button switch inside
the cab.
Select any of the following links to see detailed information on the featured positractions that we supply and design and application guide for your vehicle:
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