Content. Slewing bearing. 1 Concept of slewing bearing Function & characteristic of slewing bearing Choosing type...

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3 Content Slewing bearing 1 Concept of slewing bearing Function & characteristic of slewing bearing Choosing type Slewing bearing s materials & technique required Clearance of slewing bearings Lubrication & seal of slewing bearings Operating temperatures Service life Inspection to rings Package & storage of slewing bearings Installation & maintenance of slewing bearings Dimension form Load curve chart...26

4 Slewing bearing Dalian Running Engineering Company Limited (with registered brand RTR) is a professional manufacturer and exporter of kinds of slewing bearings and other bearings. From opened in 1998, we always supply excellent product and service to every users. Moreover, we have gained ISO9001 certificate for our control of quality. We specialized in slewing bearings and other medium and large size bearing. Product range is from 50mm to 5000mm. We are very professional in controlling the quality of our product. Since we have very strong ability both in design and technical analysis, we can provide our customers with exact, suitable, economic products also the technical services. We ve built up good relationship with our customers all over the world, especially in the Europe and USA market. Product is widely used in metallurgy, mining, petroleum exploitation, light industry, aviation, harbor/quay, vessels, military industry, instruments and meters etc. Our goal is to supply the customer with high quality, suitable products and professional, prompt service to ensure your machines keep running! RTR bearing with Reasonable price, Timely delivery, Responsible quality. RTR KEEP RUNNING! Examples for application Equipment Areal Hydraulic Platform Bogie Bearing for Vehical Excavators Harbor and Shipyard Cranes Machine Tools Mechanical Engineering Mobile Cranes Offshore Technology Packaging and Filling Machine Rail Vehicles Ship Deck Cranes Stackers and Reclaimers Steelmill Equipment Tower cranes Tunneling Machines Water Treatment Equipment Wind and Solar Energy Plants

5 Slewing bearing 1.Concept of slewing bearing 1.1 Slewing bearing s definition, structure, and classification 1) Definition Slewing bearing is a large bearing with special configuration, which can endure biggish multiply load, such as axial & radial load, overturning moment, etc. 2) Structure Slewing bearing is composed of outer ring (teeth or non-teeth), rolling element (steel ball, cylindrical roller, tapered roller), cage, inner ring (teeth or non-teeth) and seals (the one with sealed structure). 3) Classification Slewing bearing can be classified by different structure: four point contact ball slewing bearing; double row different diameter ball slewing bearing; cross roller slewing bearing; three row roller slewing bearing, etc. Slewing bearing also can be classified by teeth: slewing bearing with non-teeth, slewing bearing with external teeth, slewing bearing with internal teeth. 2. Function & characteristic of slewing bearing 2.1 Function Slewing bearing itself is featured in compact structure, convenient lead to slew, easy for installation & maintenance, which is widely used as slewing set in the fields of heavy machine, slewing platform in the steelworks, excavator grab, material taking & stacking set, material traveler, harbor machine, missile launching cage, CT set, etc. 2.2 Characteristic 1) Four point contact ball slewing bearing can take more dynamic load, and suitable for the application with speed. 2) Cross roller slewing bearing can take more static load, it s pre-interference is better for more support rigidity and slewing precision. 3) Three row roller slewing bearing is a high load capacity slewing set, different direct raceway and rollers can take load from different side. So when have the same load, it can be smaller size that can make the applocation compact. 1

6 3. Choosing type How to choose the slewing bearing type to suit the application best? Most of the companies chooses slewing bearing depends on the load chart. Most of slewing bearings work under eccentric load, take axial load (Fa), radial load (Fr) and overturning moment (M). So before choosing a suitable bearing need to have calculation for the bearing using condition, need to calculate the load for dynamic and static condition. Calculating the service life according to the safty factor of different application. Then may choose the suitable bearing. M (KN-M) (KN) /2680K Slewing bearing load curve Curve 1 means when material is 42CrMo, it is the allowable static load curve for ball bearing with allowable contact stress 3850Mpa, or roller bearing with allowable contact stress 2700 Mpa. Curve 2 means rated dynamic load curve when bearing has whole turning with reliability 90%, life time , under condition of not high radial load, low speed of turning and not high working precision. Curve 3 means when material is 50Mn, it is the allowable static load curve for the ball bearing with allowable contact stress 3400Mpa, or roller bearing with allowable contact stress 2100Mpa. The maximum load curve of the bolt is when its joint length is five times long as the bolt diameter, and the preliminary stress is 10% of the yield strength of the material. 2

7 4. Slewing bearing s materials & technique required 4.1 Main materials 1) Rings 1.1) Materials Steel 45#, 50Mn (carbon structural steel), 42CrMo (alloy structural steel). 50Mn and 42CrMo are usually used. Their chemical component and mechanics capability are showed in the form1 below. Form 1 Material 42CrMo Mn Chemic component % C Si Mn Cr Mo Mechanics Capability δ 5 ψ Reduction Elongation of area Mpa % J ð b ð s Tensile Yield strength strength AKU Impact value Standard GB/T GB/T ) Hardness Normalizing hardness of the rings is 187HB-241HB, quench & temper hardness is 229HB- 269HB, hardness of the raceway after quenching is 55HRC-62HRC. 1.3) Depth of harden After raceway surface quenching, the valid harden depth (DS) should be meet with the following form 2. Form 2 Valid raceway harden depth (DS) Unit: mm Dw(Roller/ball Diameter) Exceed To DS DS is the harden depth of raceway surface when hardness 48HRC. 1.4) Quenching soft belt of the raceway I Width of soft belt: to the rings without filling hole, when rolling element diameter Dw 25mm, width of soft belt should be less than 2Dw; when Dw>25mm,width of soft belt should be less than 3

8 50mm. As to the rings with filling hole, width of soft belt should be less than filling hole diameter plus 35mm. II Marking of soft belt: soft belt on the ring with filling hole should be the place of taper pin(filling hole) and don't need to be marked, on other rings should be set to non-installation part with the visible permanent mark S. As to the soft belt of double half rings, except setting mark, the two soft belt should be set between 180 or in one point. 2) Rolling element It is made of chrome steel GCr15 or GCr15SiMn. I Steel ball should accord with the standard of GB/T , roller should accord with the standard of GB/ II Rolling element tolerance should be chosen based on slewing bearing tolerance grade, which should accord with form 3. Form 3 Tolerance grade of rolling element to choose Bearing's Tolerance Grade Dw Steel Ball Exceed To Cylindrical Roller a 0.6 G40 G60 G100 Ⅲ 5 G20 G40 G60 Ⅱ a VLWL can be not required, surface round runout SDW should be in the range of twice standard. 3) Seal: It is usually made of NBR, iron, felt, or other things which meet the capability. Steel number comparison between China & other countries, follow form 4. Form 4 Slewing bearing material number comparison between China & Other countries Type ChinaGB (YB) USSR го ст USA AISI SAE U.K BS Japan JIS France NF Germany DIN carbon structural steel S45C C45 50Mn 50г C1050, 1052 En43C XC48 C45, CK45 alloy structural steel 42CrMo 4140 En19A 42CD4 42CrMo4

9 Material selection of slewing bearings: mainly based on working condition, size, capability required. Material selection of rolling element: GCr15SiMn is selected for larger size rolling element, GCr15 is selected for smaller size rolling element. Material selection of rings: steel 45# is for those which are low slewing speed, low precision & capability required. 50mn is for those which are higher precision & capability required, 42CrMo is for those which are higher precision & capability, higher intensity or larger size required. 5. Clearance of slewing bearings The clearance of slewing bearings is mainly used to equalize the manufacture & setting erros, which is caused by slewing bearing s support part and application s assembling part, in order to ensure the bearings right operation. It is listed in form 5 ~ 8 with with the data of clearance, which is based on slewing bearing s structure, tolerance grade, and rolling element s diameter. We also can supply slewing bearing with preload, 0 even minus clearance. Form 5 Axial clearance of four point contact ball slewing bearing μm Dpw Tolerance Grade G E D mm Axial Clearance Exceed to Min Max Min Max Min Max Form 6 Axial clearance of double row ball slewing bearing Dpw Tolerance Grade G E D mm Axial Clearance Exceed to Min Max Min Max Min Max

10 Form 7 Axial clearance of cross roller slewing bearing Dpw mm Tolerance Grade G E D Axial Clearance Exceed to Min Max Min Max Min Max Form 8 Axial clearance of three-row roller slewing bearing Dpw Tolerance Grade G E D mm Axial Clearance Radial Clearance Axial Clearance Radial Clearance Axial Clearance Radial Clearance Exceed to Min Max Min Max Min Max Min Max Min Max Min Max Lubrication & seal of slewing bearings It is necessary measure to lubricate & seal bearings effectively and sufficiently for ensuring bearings safety operation and avoiding early abnormal damage. 6.1 Lubrication of bearings Slewing bearings are usually operating in high-load & low-speed working condition, it is recommended to fill lubricate grease to do a good job. There are kinds of lubricate grease widely used, such as calcic lubricate grease, lithium lubricate grease, aluminum lubricate grease, high temperature lubricate grease, etc. Customer could choose the most suitable lubricate grease based on actual condition. It is listed with recommended lubricate grease types in form 7. 6

11 6.2 Seal of slewing bearings The seal of slewing bearings is used for avoid leakage of filled lubricate grease on one side, and the other side is to avoid inleakage of outer dust, impurity and water which can cause abnormal operation of slewing bearing. As slewing bearing is operating in the condition of highload & low-speed, there are two seal structures ususlly used, rubber and labyrinth. Rubber is widely used because of simple structure, little space occupied, good seal capability. But it will aging easily at high temperature and lose seal capability. So it is recommended to use labyrinth when in the high temperature condition. Form 9 Support structure & seal form Operating condition Lubrication Lubrication grease Part Name Type Holistic & partial cage or plastic partition rubber seal Low temperature, normal temperature, wateriness 40 ~+60 Raceway Gear Calcium base grease Graphite & Calcium base grease ZG 3 ZG 4 ZG 5 ZG S Raceway Lithium base grease ZL 1 ZL 2 Muti-genus partition 40 ~140 MoS2 compounded Calcium base grease NO.3 High temperature, wateriness 80 ~180 Gear Raceway Gear No.4 high temperature grease MoS2 compounded Calcium base grease No.4 high temperature grease ZN6-4 NO.2 ZN6-4 Labyrinth seal Normal temperature, corrosion of sea water proof Raceway Gear No.2 aluminum-base grease No.2 aluminum-base grease ZU-2 ZU-2 7. Operating temperatures Standard RTR Slewing Ring can be used in ambient temperatures from -45 to up +70, please contact us in the case of higher or lower operating temperatures. 7

12 8. Service life The service life of the slewing bearing depends on the operating conditions. The following factors are keys: Torque Output speed Duty factor Ambient temperature Lubrication etc. 9. Inspection to rings Inner & outer diameter size, height, magnetism remained, thickness of the raceway for ball, central diameter of the mounting holes, space between holes. For those with outer teeth should also inspect teeth height, constant cord thickness, etc. 10. Package & storage of slewing bearings 10.1 Package of slewing bearings Every set of slewing bearings before delivering to customers should be packed well, of which inside, outside surface and raceway are spreaded with antirust & lubricate grease. Inner package is made of plastic film, and then compositive kraft, outer package is enlaced with flax pieces Storage of slewing bearing RTR slewing bearings are well treated with antirust and oil seal before delivery, which can ensure non-rust in 12 months in the normal storage condition. When slewing bearings are in antirust period, they can be stored when their original package is in good condition. As to the storage is in excess of antirust period, slewing bearings should be treated with cleanout and oil seal again. Slewing bearings should be placed horizontally in a dry breezy flat field, which are away from chemical and other erosive things. If slewing bearings are piled up for storage, it s necessary to use at least three stow-wood in equal height, which are equally placed between every slewing bearing, and their location between up & low level should be consistent. 11. Installation & Maintenance of slewing bearings 11.1 Installation of slewing bearings Before installation of every set of RTR slewing bearings, it s necessary to check the host installation plane. Make sure that the support part has enough rigidity, and it should be mechanically processed in order to remove the sundries and burrs. Technology required to joint surface of support part should accord with form 10. 8

13 Form 10 Technology required to joint surface of support part Central circle diameter of the hole D1 or D2 mm Complanate degree a Gradient variable of unit length between circles(l=1 hole distance)on the same direction (s-t)mm Gradient variable of unit length between circles(l=1 hole distance)on the reverse direction (s+t)mm Gradient of radial width b δ Side face roughness Ra Bearing precision grade Exceed To G E D G E D G E D G E D G E D L L L L L L Side face s plane degree of working table Radial width s inclination degree of working table side face π d Circle spread There s a quenching soft belt marks S on the rings surface of every set of RTR slewing bearings offered to customers. Soft belt should be located in non-loading area or non-regular loading area (Where filler plugs locate) during installation. Installation should be begun with slewing bearings radial location, screw down the mounting bolt and check the slewing condition. In order to ensure the slewing steadiness of bearings, gear mesh checking is needed before screwing down the bolt completely. It should has enough preload when screwing down the bolt, which should be 70% of yield strength of bolt material. Mounting bolt should be used with Q & T flat gasket not spring gasket. The fastening bolt must reach the required preload when assemble the slewing bearing. Preload of different diameter bolt should accord with form 11.

14 Form 11 Bolt diameter Bolt rigidity grade ISO0898 Yielding limit M N/mm 2 M> Forced stress area of thread mm 2 Section area of thread mm 2 Pre-screwing tightness of bolt installation FMN Academic tightness moment MANm Torsional moment Nm M'=0.9MA Pre-screwing tightness of bolt installation FMN Academic tightness moment MANm Torsional moment Nm M'=0.9MA Pre-screwing tightness of bolt installation FMN Academic tightness moment MANm Torsional moment Nm M'=0.9MA M M M M M M M M M M M M M M M M M Thread hydraulic Thread hydraulic Thread hydraulic tension set needed tension set needed to tension set needed to M to use use use M M M M Maintenance of slewing bearings RTR slewing bearings should be checked with mounting bolt preload moment to see whether it s qualified as required after 100 working hours. Since the first check, it should be repeated every 500 working hours. After installation, some lubrication grease should be filled into bearings, when doing this, remember to slew the bearings in order to ensure grease equal arrangement. It s normal for slewing bearings to lose some lubrication grease after working for some time, so grease refilling is necessary for working slewing bearings once every 50~100 working hours. This period should be reduced in the working condition of high temperature and dust. This refilling is also needed when machine stops turning for some time. 10

15 12. Dimension form 12.1 Single-row four point contact ball slewing ring bearing The single-row four point contact ball slewing ring is composed of 2 seat-rings.it features compact in design,and light in weight.the balls contact with the circular race at four points,via which the axial force,radial force and resultant moment may be born simultaneously. It may be used for slewing conveyers,welding arm and positioner,light,medium duty cranes,excavators and other engineering 11

16 No. Toothless Basic type Ext Toothing Int Toothing D L D L D L mm mm mm mm mm mm mm mm Configuration size Mounting Structural size Gear Data Ext Gear Int Gear Tangential Tooth lood D d H D 1 D 2 Φ D 3 d 1 H 1 b m D e D e Norm temp m mm mm mm mm mm mm mm -aliz -eri m n n1 h x Z Z -ing -ng Z T Weight (kg) 10 4 N 10 4 N _ _ _ _ _ _ _ _ _ _ _ _ ' '

17 No. Toothless Basic type Ext Toothing Int Toothing D L D L D L mm mm mm mm mm mm mm mm Configuration size Mounting D d H D 1 D 2 Φ D 3 d 1 H 1 b m D e D e Norm temp n m m Structural size Gear Data Ext Gear Int Gear Tangential Tooth lood mm mm mm mm mm mm mm -aliz -eri n1 h x Z Z -ing -ng Z T ' ' N 10 4 N ' Weight (kg)

18 No. Toothless Basic type Ext Toothing Int Toothing Configuration size Mounting D L D L D L mm mm mm mm mm Structural size Gear Data Ext Gear Int Gear Tangential Tooth lood D d H D 1 D 2 Φ D 3 d 1 H 1 b m D e D e Norm temp m mm mm mm mm mm mm mm -aliz -eri n m n1 h x Z Z mm mm mm -ing -ng Z T 10 4 N 10 4 N ' ' Weight (kg) ' '

19 Toothless Basic type Ext Toothing Int Toothing Configuration size Mounting Structural size Gear Data Ext Gear Int Gear Tangential Tooth lood D d H D 1 D 2 Φ D 3 d 1 H 1 b m D e D e Norm temp No. m D L D L D L mm mm mm mm mm mm mm mm mm mm mm mm n m n1 h x Z Z -aliz -eri mm mm mm -ing -ng Z T 10 4 N 10 4 N ' ' ' ' ' Weight (kg) 15

20 No. Toothless Basic type Ext Toothing Int Toothing Configuration size D L D L D L mm mm mm mm mm Mounting Structural size Gear Data Ext Gear Int Gear Tangential Tooth lood D d H D 1 D 2 Φ D 3 d 1 H 1 b m D e D e Norm temp n m n1 h x Z Z mm mm mm mm mm mm mm -aliz -eri m mm mm mm -ing -ng ' ' Weight (kg) 16

21 12.2 Cross roller bearing The single-row crossed roller slewing ring is composed of two seat-rings.it features compact in design,light in weight,high precision and small fitting clearance. As the rollers are 1:1cross aranged,it is suitable for high precision mounting and capable to bear axial force,rsultant moment and considerable large radial force. The single-row crossed roller slewing rings are widely used for hoisting,transporting,engineering machines as well as for military products. 17

22 No. Basic Type Configuration Mounting Size sturctural size Gear Date Ext Gear Int gear Noma Toothless Ext Toothless Int Toothless D d H D 1 D 2 Φ D 3 d 1 H 1 b D e D e lizh ing D L D L D n n1 h x m Z Z L mm mm mm mm mm mm mm mm mm mm mm mm Tangential Tooth load Temp erin g weigh t (kg) mm mm mm N N

23 No. Basic Type Configuration Mounting Size sturctural size Gear Date Ext Gear Int gear Noma Toothless Ext Toothless Int Toothless D d H D 1 D 2 Φ D 3 d 1 H 1 b D e D e lizh ing D L D L D n n1 h x m Z Z L mm mm mm mm mm mm mm mm mm mm mm mm Tangential Tooth load Temp erin g weigh t (kg) mm mm mm N N

24 12.3 Double-row ball slewing ring type The double-row Ball slewing beraring has three seat-rings.the steel balls and the spacers may be directly arranged into the upper and lower races.two rows of steel balls with different diameters are fitted according to the force bom. Such open mode fitting features extraordinary convenience.the load angles of both upper and lower races are 90,which enable the bearing to bear large axial force and the tipping moment. When the radial force is larger than 1/10 of the axail force the races should be newly designed. As the axle and the dimension of the double-row ball slewing bearing are rather large,the bearing construction is sturdy,hence it is especially suitable for tower cranes which require working radius over medium range,mobile cranes and loading and unloading 20

25 No. Basic Type Configuration size Mounting size sturctural Ext Gear Toothless Ext Toothless INt Toothless D 1 D 2 d n1 d m1 L b m d a d a Gear date Int Gear weigh t kg D L D L D L D d H mm mm d n2 d m2 mm n n 1 H 1 h mm mm mm Z mm Z mm mm mm mm mm M M M

26 Basic Type Configuration Mounting size sturctural Gear Ext Gear Int Gear size date No. Toothless Ext Toothless INt Toothless D 1 D 2 d n1 d m1 L b m d a d a D L D L D L D d H mm mm d n2 d m2 mm n n 1 H 1 h mm mm mm Z mm Z mm mm mm mm mm M weigh t kg

27 12.4 Three-row roller slewing ring type Three-row roller slewing bearing has three seat-rings,which separate the upper,lower and radial races,via which the load of each row of the rollers may be specified.it may bear different loads simultaneously and its load capacity is the largest one among the four models. Thanks to the large size of its axle and radius,it is sturdy and especially suitable for hearvy-duty machines which require large working radius.such as bucket-wheel excavators,wheeled cranes,ship cranes,ladle turret,heavyduty mobile cranes etc 23

28 sturctural Basic Type Configuration Mounting Size Gear Date Ext Gear Int Gear No size. φ M Toothless Ext Toothless Int Toothless D d H D1 D2 n 0 1,2,3 n1 H1 h b x m De Z De Z kg φ φ T M M M M M M M M M M M M Wei ght 2

29 sturctural Basic Type Configuration Mounting Size Gear Date Ext Gear Int Gear No size. φ M Toothless Ext Toothless Int Toothless D d H D1 D2 n 0 1,2,3 n1 H1 h b x m De Z De Z kg φ φ T M M M M Wei ght 25

30 26

31 27

32 28

33 2

34 30

35 31

36 32

37 33

38 3

39 35

40 36

41 37

42 38

43 3

44 0

45 1

46 2

47 3

48

49 5

50

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