Manitowoc National Crane NBT30H-2, Руководство по обслуживанию

Страница: 15 / 194

National Crane
03-20-2019 Control # 613-06
1-5
NBT30H-2 SERVICE MANUAL INTRODUCTION
1
10
Hoses and Tubes
Inspection
Check hoses carefully. Do not use your bare hands to check
for leaks.
Tighten all connections to recommended torque.
If the hose end connections are damaged, always replace
the hose or tube. Damaged, dented, crushed, or leaking
hose fittings restrict oil flow and the operation of the parts
being served. Fittings showing signs of movement from their
original position have failed and must be replaced.
Be sure hoses are in good condition. If in doubt, replace
them.
Replace hoses if any of the following is evident Figure 1-3:
• Evidence of kinking or crushing (1)
• Chaffing or cuts; wire is exposed (2)
• Damaged or leaking fittings (3)
• Localized ballooning (4)
Installation
1. When installing a new hose, loosely connect each end
and make sure the hose takes up the designed position
before tightening the connection. Clamps should be
tightened sufficiently to hold the hose without crushing
and to prevent chafing.
2. If a hose is replaced on a part that moves during
operation, be sure it moves freely by moving the part
through its complete range of movement.
3. Be sure any hose which has been installed is not kinked
or twisted.
Free moving, unsupported hoses must never rub on each
other or related work surfaces. This causes chafing and
reduces hose life.
Bearings
Antifriction Bearings
When an antifriction bearing is removed, cover it to keep out
dirt and abrasives. Wash bearings in non-flammable
cleaning solution and allow them to drain dry. The bearing
may be dried with compressed air but do not spin the
bearing. Discard the bearings if the races and balls or rollers
are pitted, scored, or show signs of heat damage. If the
bearing is serviceable, coat it with oil and wrap it in clean
waxed paper. Do not unwrap new bearings until time of
installation. The life of an antifriction bearing will be
shortened if not properly lubricated. Dirt in an antifriction
bearing can cause the bearing to lock resulting in the shaft
turning in the inner race or the outer race turning within the
cage.
Double Row, Tapered Roller
Double row, tapered roller bearings are precision fit during
manufacture and components are not interchangeable. The
cups, cones, and spacers are usually etched with the same
serial number and letter designator. If no letter designators
are found, wire the components together to assure correct
installation. Reusable bearing components should be
installed in their original positions.
Heating Bearings
Bearings which require expansion for installation should be
heated in oil not to exceed 121° C (250 °F). When more than
one part is heated to aid in assembly, they must be allowed
to cool and then pressed together again. Parts often
separate as they cool and contract.
Installation
Lubricate new or used bearings before installation. Bearings
that are to be preloaded must have a film of oil over the entire
assembly to obtain accurate pre-loading. When installing a
bearing, spacer, or washer against a shoulder on a shaft, be
sure the chamfered side is toward the shoulder.
DANGER
High Pressure/Temperature Hazard!
Exercise extreme care around pressurized hydraulic
hoses or tubes. DO NOT work on a hydraulic system
while it is in operation or until all pressure is released.
Hydraulic oil is hot, it can cause severe burns.
Pressurized hydraulic oil can cause death or serious
injury.
Stay clear of all hydraulic oil leaks. Relieve system
pressure and use a piece of cardboard or paper to
check for leaks. Do not use your hands.
Fluid injected into skin must be surgically removed
within a few hours by a doctor familiar with this type of
injury or gangrene will result.
!
FIGURE 1-3
1
2
3
4