Installation Manual
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Installation and Maintenance Instruction

Slewing Bearing Introduction
Thanks for choosing “XUZHOU HELIN “ brand slewing bearing, our products execute the Machinery Industry Standard of P. R.C JB/T2300-2011 standard, please read this manual carefully before installing and operating our products.
Standard design slewing bearing are suitable for operating temperature ranging from -20  ℃  to 60  ℃ 



1.  Transportation and storage 
    Transport pallets with forklift or crane horizontally and make sure they cannot slip away, never transport slewing bearing vertically without any steel bracket.
As supplied slewing bearings are packaged for storage in a covered store and for a period not exceeding six months, light surface corrosion can usually be removed from exterior surface and it is more important that the raceway is well greased and dust free, in extreme cases after long term storage bearings may need professionally reconditioning before installation. 

2.  Installation preparation 
  • Unpacking slewing bearing
Unpack the slewing bearing carefully, do not damage the internal seals
  • Mounting structure requirement for slewing bearing
   The thickness of the supporting plates should be no less than that indicated below –which is offered as a rough approximation only.
Raceway Dia (mm) 500 750 1000 1250 1500 2000 2500 3000
Min Support
Thickness (mm)		 25 30 35 40 50 60 70 80
The width of the supporting surface must be at least equal to the width of the ring it supports
Permissible flatness deviation and deflections in supporting structure 
In order to make the slewing bearing turn smoothly, the mounting structure should be stress-relived after welding procedure, The maximum permissible out-of-flatness, including slops and axial deflections is detailed in the respective tables. See table 1
Regarding the slope of the machined surfaces, the figures shown in the table refer to a support width of 100mm. another important factor is to ensure that the maximum value is reached only once per 180°sector.
As in the case of out-of-flatness, any deflections in the supporting structure must not allowed to lead to localized buckling which might cause tight spots in the raceways. This could easily lead to over-loads. For this reason, the same conditions as for the out-of-flatness will apply.
For the maximum permissible deflections in the Table 2, the permissible slope may be twice the value”P” in Table 1 (Reference width 100mm)
The maximum permissible axial deflections “V” shown in Table 2 apply to all bearings types and are indicated as a function of the track diameter of the bearing
Table 1: 
Permissible out –of-flatness including slope “p” of the machined support surface
Track diameter Out of flatness including slope per support surface “P” in mm
DL(mm) Single-row ball 
four point contact ball bearings		 Double-row ball
Eight point contact ball bearings		 Roller bearing
Slewing bearings
To 1000 0.15 0.20 0.10
To 1500 0.19 0.25 0.12
To 2000 0.22 0.30 0.15
To 2500 0.25 0.35 0.17
To 4000 0.30 0.40 0.20
4000-6000 0.40 0.50 0.30
6000-8000 0.50 0.60 0.40
Table 2 :
Maximum permissible axial deflections for contact surfaces at maximum operating load 
Track  Dia (mm)
(DL)		 To
1000		 To
1500		 To
2000		 To
2500		 To
3000		 To
3500		 To
4000		 To
5000		 To
5500		 To
6000
Max Axial deflections in mm (V) 0.6 0.8 1.0 1.3 1.6 2.0 2.5 3.0 3.6 4.2
Besides the inner and outer ring of a slewing bearing must rest fully on the supporting structure surface.
  • Mounting elements selection
Choose bolts of recommended grade, quality class 10.9(metric) or SAE grade 8 bolts, Grade 12.9 bolts are only used in very rare circumstances.
Do not use a fully treaded bolt.
Only use treated hardened flat washers.
Use of elastic washers is absolutely prohibited. Do not reuse bolts, nuts and washers.

3.  Installation of Slewing Bearing
  • Hardness gap on slewing bearings
The hardness gap occurs in the process of raceway inductive hardening and is located between the end and the beginning of the hardening. These areas must be placed in the area of least load. Ideally at zero load when installing slewing bearing.
The position of the hardness gap on each of the slewing ring can be told as follows:
Slewing Bearing Internal gear type External gear type Non Gear type
Inner ring S marking Filler plug S marking or filler plug
Outer ring Filler plug S marking S marking or filler plug
  •  
  • Fastening of slewing bearing
Before fastening, use a feeler gauge to check whether the surface of the slewing bearing is completely supported by the mounting structure. If this is not the case, the support surfaced of the mounting structure must be reworked. Please follow the sequence pattern below to install bolts:
 
Tighten all fasteners lightly, and tighten to a specified value using a properly calibrated torque
Wrench, hydraulic devices are advisable.
When tightening the whole bolt circle, ensure a uniform tightening torque. 
The recommend bolt tightening torque values are listed in the table below:
    Bolt
Thread size		 Bore Dia
（mm）
DIN/ISO 273		 Tightening Torque at μ=0.14Nm
Bolt class 8.8 Bolt Class 10.9
M12 14 79 117
M14 16 126 184
M16 17.5 193 279
M18 20 270 387
M20 22 387 558
M24 26 666 954
M27 3330 990 1395
M30 33 1350 1890
UNC   Grade 5 Grade 8
UNC5/8”-11 18 180 260
UNC3/4”-10 21 320 460
UNC7/8”-9 25 520 730
UNC1”-8 27.5 770 1100
UNC1 1/8”-7 32 970 1560
UNC 1 1/4”-7 35 1370 2190
UNF   Grade 5 Grade 8
UNF5/8”-18 18 210 290
UNF3/4”-16 21 360 510
UNF7/8”-14 25 580 820
UNF1”-12 27.5 860 1210
UNF1 1/8”-12 32 1100 1760
UNF 1 1/4”-12 35 1520 2440
The slewing bearing should be rotated during tightening process as this will indicate the development of any tight spots, the cause of which must be investigated.
The bolt torque should be checked before machine is finally operated to check for any loss of pre-load due to the structure settling.  
  • Pinion installation
The pinion should be located approximately at 90°of the major loading axis. Adjust the driving pinion to maximum eccentric point of the gear ring, usually with green or red paint covering 2 or 3 teeth. The backlash of the slewing bearing gear and pinion must be within the limits of the calculated values or minimum at 0.05 x module. When several pinions are used, each one must be adjusted to the same conditions. During test, make sure good alignment of the pinion and of the slewing bearing axes permits a satisfactory contact cross all gear width. Before running, lubricate the slewing bearing gear and pinion gear.
  • Running test
After final tightening of all fasteners:
Rotate the ring for at least 3 turns. Recheck the backlash value on the gear mesh over one full revolution. Measure the total deflection under a know load. The checked point should be maked.It is advisable to register these values in a maintenance logbook specific to the machine.
Deflection measurement under load mounted slewing bearing
Operating process:
Place a measuring device between the two rings as close as possible to the raceway on the main load axis: precision grade 0.1mm minimum.
Calibrate to zero under a known load. Apply a measured load. Read the deflection value at the
point considered. Repeat this measurement in the previously marked points. Take into account the deflection of the support structure and the fasteners elongation corresponding to the instrument position.

4.  Greasing and Daily Maintenance
       Maintenance involves regular lubrication of raceways and gear together with inspection of the fastening bolts and wear of the bearing.
4.1 Greasing and regressing 
A suitable lubrication is essential for the longevity of the raceways and gears. Please fully grease the raceway with EP2 based grease or equivalent grease before installation .The greasing frequency varies according to utilization and working environment. We would recommend regressing every 60 hours for ball type slewing bearing, every 40 hours for roller type slewing bearing. The frequency should be reduced when conditions of application are several ,such as high temperature, high humidity, dust and large temperature difference environment.
Greasing is required before and after a long non-operation period.
Slowly rotate the bearing while greasing the raceway.
During cleaning prior to regreasing the gear, check carefully for any foreign body at the tooth root ring and pinion. Check the even load distribution of the pinion on the entire width of the ring gear and correct alignment of the axes if needed. Check the backlash of the pinion and ring gear.
4.2 Preventive maintenance
A visual examination makes it possible to ensure the integrity of the protective seals. After greasing, wipe clean residue of old grease and check for pollutions such as sand, cal, metallic particles, ect. it is particularly important to check that the required preload level of the bolts is still maintained as the fasteners of the slewing bearings are essentially working in fatigue. We recommend retightening the fasteners after the first two or four months of utilization and then proceeding to a systematic yearly check. if any bolt is found loose, a further in deep examination is essential. The necessary preservative measures must then be exercised.
 
When inspecting, the following method can be used (approximately valid for crane operation)
Inspection No. Number of Operating Hours Inspection Action
1 About 200 hours
  • Inspect all bolts torque
  •  if more than 10% of the bolts are loose, another inspection is necessary after about 200 operating hours
2 About 600hours Inspect all bolts torque
3 After 2000 hours
  • If one or more bolts are loose to less than 80% of the prescribed torque, these and both adjoining bolts must be replaced by new ones.
  • If 20% of the bolts have less than 80% prescribed torque, all bolts must be replaced by new ones
Each 12000 hours Replace all bolts by new ones
In addition to the fixing bolts check, raceway wear checking is also carried out in operation (mainly at significant important rotary connections) using the measurement method “titling clearance”. The tilting clearance is the difference of the mutual ring displacement in axial direction measured under load by minimum and maximum tilting moment.
4.3 Seals 
Seal is usually specific to each manufacturer and the profiles and groove dimensions vary.
Seals must be inspected at least annually and replaced as required. Standard nitrile seals will perish in approximately 5 years.
 
The installation and maintenance manual provide important 
instructions and must be precisely followed.
More detailed information will be provided by your request.

 
Phone/Whatsapp:
+86-516-8788 0390
+86 180 8679 0390
Email:
tinaxzhelin@gmail.com
Opening hours:
Mon. - Fri. 8:30 - 18:00
ABOUT US
We are Xuzhou Helin Slewing Bearing Co.,Ltd Slewing bearing factory in Xuzhou city . Our slewing bearing size from 100 mm - 5000 mm with standard and non- standard models . Good product quality, short delivery time, suitable price, high cost performance . welcome to contact us . 
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