Screw liftThe main reason for the daily damage of the slewing drive may be clear to everyone. It is the widely used calculation method of contact stress and static capacity, which is based on the premise that the slewing drive is uniformly stressed and the effective contact length of the roller is 80% of the roller length. .Obviously, this premise is not in line with the actual situation.This is another reason why the rotary drive is easily damaged.In daily work, what are the reasons for the damage of the slewing drive? Let's share with you the analysis of the damage factors of the slewing drive.
XNUMX. The following suggestions are put forward for the problem of damage to the slewing drive:
1. Through finite element analysis, appropriately increase the thickness of the plate at the connecting part of the turntable and the rotary drive in order to improve the structural rigidity of the turntable.
2. When designing a large-diameter slewing drive, the safety factor should be appropriately increased; appropriately increasing the number of rollers can also improve the contact between the rollers and the raceway.
3. Improve the manufacturing accuracy of the rotary drive, focusing on the heat treatment process.It can reduce the intermediate frequency quenching speed, strive to obtain a larger surface hardness and hardening depth, and prevent quenching cracks on the surface of the raceway.
XNUMX. Heat treatment state
The processing quality of the rotary drive of the screw lifter itself is greatly affected by the manufacturing accuracy, the axial gap and the heat treatment state. The factor that is easy to ignore here is the effect of the heat treatment state.Obviously, in order to prevent cracks and depressions on the surface of the raceway, it is required that the raceway surface has sufficient hardness, as well as sufficient hardened layer depth and core hardness.According to foreign information, the depth of the hardened layer of the raceway should be thickened as the rolling elements increase, the deepest can exceed 6mm, and the hardness of the core should also be higher, so that the raceway will have a higher resistance to crushing.Therefore, the depth of the hardened layer on the surface of the rotary drive raceway is insufficient, and the hardness of the core is low, which is also a factor that causes its damage.
Third, the structural stiffness of the turntable
The slewing drive of the screw lift is an important component that transmits various loads between the turntable and the chassis. Its rigidity is not large, and it mainly depends on the structural rigidity of the chassis and the turntable supporting it.Theoretically, the ideal structure of the turntable is a cylindrical shape with large rigidity, so that the load on the turntable can be evenly distributed, but it is impossible to achieve it due to the height of the whole machine.The results of the finite element analysis of the turntable show that the bottom plate connected to the turntable and the slewing drive deforms greatly, and it is more serious under large unbalanced load conditions, which causes the load to be concentrated on a small part of the rollers, thereby increasing the size of a single roller. The pressure received; especially serious is that the deformation of the turntable structure will change the contact condition of the roller and the raceway, greatly reducing the contact length and leading to a substantial increase in contact stress.