Swing Bearing; Description; Maintenance - Manitowoc Grove RT9130E-2 Service And Maintenance Manual

RT9130E-2 SERVICE MANUAL

SWING BEARING

Description

The swing bearing is an anti-friction roller bearing that mates
the superstructure to the carrier. The bearing inner race is
bolted to the superstructure and the outer race is bolted to
the carrier. The inner race contains grease fittings for
lubrication of the bearing which are hosed to two fittings at
the front of the turntable center section. The outer race has
gear teeth that mesh with the pinion gear of the swing
gearbox to provide rotation.

Maintenance

General
The swing bearing is the most critical maintenance point of
the crane. It is here, at the centerline of rotation, that
stresses of loads are concentrated. In addition, the bearing
provides the only attachment between the superstructure
and carrier. Therefore, proper care of the bearing and
periodic maintenance of the turntable-to-bearing attach bolts
IS A MUST to ensure safe and efficient operation.
Torquing Turntable Bolts
General
WARNING
Failure to maintain proper torque of the turntable bearing
attaching bolts will result in damage to the crane and
possible injury to personnel.
Maintaining proper torque value for bolts is extremely
important for structural strength, performance, and reliability
of the crane. Variations in torque can cause distortion,
binding, or complete separation of the superstructure from
the carrier.
CAUTION
Repeated re-torquing may cause bolts to stretch. If bolts
keep working loose, they must be replaced with new bolts
of the proper grade and size.
Proper identification of bolt grade is important. When marked
as a high strength bolt (grade 8), the serviceman must be
aware of bolt classifications and that he is installing a high
strength heat-treated tempered component and the bolt
Grove
must be installed according to specifications. Special
attention should be given to the existence of lubricant and
plating that will cause variation from dry torque values. When
a high strength bolt is removed, or un-torqued, the bolt must
be replaced with a new bolt of the same classification.
It is mandatory that bearing attaching bolts be inspected
for lack of torque and retorqued, as required, after the first
300 hours of crane operation. The bolts may loosen in
service due to vibration, shock-loads, and temperature
changes, therefore, periodic inspection should be
accomplished every 500 hours thereafter, ensuring the
bolts are properly torqued.
Refer to Fasteners and Torque Values, page 1-18 for
information on torque wrenches and torque multipliers.
Torque Values
Refer to Fasteners and Torque Values, page 1-18 for the
torque value for the turntable bolts.
Tools Required
Special Turntable Bolt Torquing Tools (Figure 6-3) illustrates
and lists the complete set of special tools required to torque
the turntable bolts.
Inner Race Torquing
1. Extend and set the outriggers. Fully elevate the boom.
2. Torque eight bolts to 80% of their specified torque value
using the following sequence pattern: 11, 31, 21, 1, 16,
36, 26, and 6 (Figure 6-2). Tools used are the socket,
multiplier, backlash adapter, necessary extensions, and
torque wrench.
3. Return to bolt 1 and torque all 40 bolts sequentially in a
clockwise direction to their final torque value specified.
Outer Race Torquing
1. Extend and set the outriggers. Fully elevate the boom.
2. Torque eight bolts to 80% of their specified torque value
using the following sequence pattern: 10, 28, 19, 1, 15,
33, 24 and 6 (Figure 6-2). Tools used are the socket,
multiplier, backlash adapter, necessary extensions, and
torque wrench.
3. Return to bolt 1 and torque all 36 bolts sequentially in a
clockwise direction to their final torque value specified.
Published 11-22-2016, Control # 345-12
SWING SYSTEM
WARNING
6
6-11