- Requirements forinstalling seat frame
The slewing bearing must be installed on a seat frame to transmit load. there are various forms in the installation seat frame, and their structures are shown in Fig. 3. In order to transmit the load better, seat frame for installation must be of enough rigidity and precision, and the rigidity of each part of the seat frame should be equal.Seat frame and slewing bearing can only be connected by bolts and nuts, and welding is prohibited absolutely. For the specific requirements, refer to following Tables 3.
- Requirement for the driving pinion
Most slewing bearings of our company have gears and their tooth height have been revised (addendum coefficient is +0.5) to reduce pressure evidently, and tooth height has been reduced (cut a certain part of tooth top) to avoid the interference of tooth root of pinion. Sometimes , tooth height of pinion must be revised too, so as to avoid geometrical interference when the quantity of pinion teeth is smaller than 18. This should be noticed when selecting a gear to match the pinion. The number of pinions to be used should be determined according to the driving force that the system needs. We have already given he max circumferential force that a loading tooth can bear in the sample
- Requirements for installing bolts
Appropriate bolts and fastening force should be chosen for installing slewing bearing.Bolt size should meet the requirements of GB/T5782-2000 and GB/T5783 -2000, and strength should not be lower than 8.8 grade specified in GB/T3098.l-2000. Our company proposes to use 10.9 grade high-strength bolts, and chooses 8.8 and 12.9 grade high-strength bolts for special use. Spring washers can not be used when installing slewing bearing. The size of plain washer must meet the requirements of GB/T97.l-1985 and GB/T97.2-1985, and should be treated by hardening and tempering. The clamping length of the bolt must be greater than or equal to 5d (d is the nominal diameter of bolt). When the bolt is being tightened on seat frame, a certain pre-tightening force should be guaranteed and it is generally 0.7 times of the yield limit of the bolt.
Note: (1) When the bolt size does not meet GB/T5782-2000 or GB/ T5783-2000, the value in the table needs to be calculated separately;
(2) The total coefficient of friction between the bolt head and clamping surface is 0.14, a little oil can be applied on screw thread .