Eaton CLSM0200, Руководство по обслуживанию

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General Information
Clutch Disc Friction Material
Organic facings, often called “rag” facings, get their name
from the high concentration of organic rubber and binder
agents that make up their composition. Fiberglass cord (or
similar material) is woven into the material matrix and adds
burst strength and improves friction and wear properties.
Asbestos has not been used in organic friction material since
the early 1980's. Organic facings are used without exception
in passenger car and light truck applications. This is so
because of smooth engagement properties and the relative
light torque loads imposed on the clutch. In general, organic
friction material lacks in performance in wear rate, coefficient
of friction (ability to carry torque), and resistance to fade
(abuse tolerance) when compared to cera-metallic friction
material. The use of organic friction material in heavy vehicles
has significantly declined over the past decade. Wear life and
its maximum limit to 1,400 lb-ft. (1892 N•m) of torque in
15.5" clutches are the primary reasons.
Cera-metallic (Ceramic) friction facings are composite mate-
rial (copper, sand and other friction modifiers and binder
agents). The dry raw materials are mixed in bulk, poured into
die cavities, compressed, sintered in an controlled atmo-
sphere, then brazed into a steel backer plate to facilitate rivet
attachment to the driven disc. Compared to organic friction
material, cera-metallics have improved performance in the
areas of wear rate, resistance to fade (abuse tolerance), and
coefficient of friction (ability to carry torque). It is for this rea-
son that cera-metallics make up the vast majority of OEM
builds.
Clutch Slippage
Slippage will cause significant heat build-up and rapid wear of
the clutch pack. If the clutch pack temperature raises beyond
the facing threshold temperature, the facing may disintegrate.
Slippage is the result of loss of clamp load due to lack of
adjustment, loading the clutch beyond its design torque rat-
ing, or the clutch has reached the end of its design life. With
the ability to re-rate an electronic controlled diesel engine, it is
quite easy to delivery torque to the clutch beyond its design
capacity. Before an engine re-rating is performed, confirm that
the clutch and other drivetrain components are capable of car-
rying the increased torque and power.
Clutch Torque Capacity
It is imperative to understand the factors that influence fric-
tion force because this device transmits torque via friction.
The fundamental equations that describes friction is:
F(f) = uN
Where F(f) = Force due to friction
U = Coefficient of friction
N = Load applied to the friction interface
T = F(f)r
Since torque (T) is equal to force friction F(f) multiplied by the
moment arm (R) (distance from application of force to center
or rotation) must be known. To exactly calculate the moment
arm, the mean radius of a clutch (R), integration must be per-
formed. However, for clutches in the size range offered by
Eaton, the calculation can be simplified to:
(r) = (ID + OD) / 4
Clutch Wear
Clutch wear happens because the clutch discs slip relative to
the engine flywheel and the pressure plate surface, and in the
case of a two plate clutch, the intermediate plate, during vehi-
cle launch and gear change. As the clutch disc friction mate-
rial and mating flywheel and pressure plate surfaces wear, the
gage thickness of the clutch pack decreases (moving the
pressure plate closer to the engine flywheel). This movement
of the pressure plate causes the pressure spring(s) to elon-
gate and loose clamping load. If clamping load is allowed to
decrease beyond a critical point, the clutch will be unable to
carry full engine torque and slip.
Cover Assembly
The cover assembly, constructed of either stamped steel or
cast iron, is bolted to the flywheel. It contains the pressure
plate, which is fitted to the cover with pressure springs. It also
contains the release bearing and levers, which move the pres-
sure plate back and forth, thereby making or breaking contact
with the disc assembly.