What are the effects of damage caused by Dual Axis Slewing Drive?
When the Dual Axis Slewing Drive damage occurs, which led to the phenomenon of the final cause, there are many factors together, then today in this, Yiyang Longma Bearing Co., Ltd. Xiaobian for everyone in detail, the relevant Resulting in damage caused by biaxial rotation drive what kind of impact.
Dual-axis rotation in the normal operation of the operation, there may be different levels of damage, then for these circumstances, how to better correct the root cause of the problem, this is to our common attention, detailed as follows:
1, the impact of safety factor
The Dual Axis Slewing Drive is often operated at low speed and high load conditions. Its carrying capacity is generally expressed as static capacity, and the rated static capacity is denoted by C0 a. The so-called static capacity refers to the track deformation of δ to 3d0 / 10 000 Dual Axis Slewing Drive carrying capacity, d0 for the rolling body diameter. The combination of external loads is generally expressed as the equivalent load Cd. Static capacity and equivalent load ratio known as the safety factor, recorded as fs, which is designed and selected dual-axis rotary drive the main basis. When using the method of checking the maximum contact stress between the roller and the raceway to design the Dual Axis Slewing Drive, take the allowable thread contact stress [σk line] = 2.0 ~ 2.5 × 102kN / cm. At present, most manufacturers are based on the size of the external load on the dual-axis rotary drive selection calculation. According to the available information, the current small tonnage crane dual-axis rotary drive than the large tonnage crane double-axis rotary drive contact stress is small, the actual safety factor is higher. The greater the tonnage of the crane, the greater the diameter of the Dual Axis Slewing Drive, the lower the manufacturing accuracy, the lower the safety factor is actually lower, which is the large tonnage crane dual-axis rotary drive than the small tonnage crane dual-axis rotary drive more easily damaged The root cause. It is generally believed that more than 40 t crane Dual Axis Slewing Drive, the line contact stress should not exceed 2.0 × 102 kN / cm, the safety factor should be not less than 1.10.
2, turntable structural stiffness
The Dual Axis Slewing Drive is an important part of the load between the turntable and the chassis, and its stiffness is not large, mainly depends on the structural rigidity of the chassis and turntable supporting it. In theory, the ideal structure of the turntable for the large stiffness of the cylindrical, so that the turntable can withstand the load evenly distributed, but by the whole height limit can not be done. The finite element analysis of the turntable shows that the turntable and the Dual Axis Slewing Drive are connected to the bottom plate with large deformation, which is more serious under the large load condition, which causes the load to act on the small part of the roller, thus increasing the single roll The pressure is affected by the turntable structure will change the contact between the roller and the raceway, greatly reducing the contact length and lead to a substantial increase in contact stress. The current widely used contact stress and static capacity of the calculation method, are driven by double-axis rotation uniform force, and the effective contact length of the roller roller length of 80% of the premise. Obviously, this premise is not consistent with the actual situation. This is another reason why the Dual Axis Slewing Drive is easy to damage.
3, the impact of heat treatment
The processing quality of the Dual Axis Slewing Drive itself is greatly influenced by the manufacturing accuracy, the axial clearance and the heat treatment state, and the factors that are easily overlooked here are the effects of the heat treatment state. Obviously, to make the raceway surface does not produce cracks and depression, it is required to have sufficient hardness in addition to the raceway surface, but also must have enough hardened layer depth and hardness of the heart. According to foreign information, the depth of the track hardening layer should be increased with the rolling body thickening, the deepest more than 6 mm above the core hardness should be higher, so that the raceway will have a higher anti-crushing capacity. So the Dual Axis Slewing Drive raceway surface hardened layer depth, heart hardness is low, but also cause one of the reasons for its damage.
In view of the above three are likely to lead to damage caused by the two-axis rotation of the reasons, in this, we must pay attention to, then in addition, but also to remind you that the Dual Axis Slewing Drive damage handling methods.
1, through the finite element analysis, appropriate to increase the turntable and Dual Axis Slewing Drive connected parts of the plate thickness, in order to improve the turntable structural stiffness.
2, the design of large diameter Dual Axis Slewing Drive, should be appropriate to increase the safety factor; appropriate increase in the number of rollers can also improve the roller and roller contact conditions.
3, to improve the manufacturing accuracy of dual-axis rotary drive, focusing on the heat treatment process. Can reduce the frequency quenching speed, and strive to obtain a larger surface hardness and hardened depth, to prevent the surface of the raceway quenching cracks.