Current Situation and Development Trend of Special Bearings for Industrial Robots
Hits:Updated:2016-10-09 16:10:05【Print】
| 1. Design principles of supporting bearings for industrial robots Usually, the general bearing structure and the determination of the main parameters are based on the rated dynamic load as the objective function, under certain constraints, through optimization. Thin-walled bearings in use, not only have a larger dynamic load rating to ensure that the bearing has sufficient load capacity, but also has a strong stiffness and a smaller friction torque to ensure the robot host positioning accuracy, flexible operation. Therefore, in the bearing design and analysis process, the three indexes of dynamic load, stiffness and friction torque should be taken as the objective function for multi-objective optimization design, and the influence of these parameters on the bearing performance will be considered emphatically. Flexible bearing belongs to the special thin-wall ball bearing. Some designs can refer to the design method of the thin-wall ball bearing, such as the main parameter ball diameter, the groove curvature coefficient, the choice and calculation of the groove diameter, the choice of materials, heat treatment and car and grinding process. However, due to its special requirements, its main parameters such as the number of balls, ball pitch circle diameter, the diameter of the retaining wall, ball angle, the diameter and shape of the cage ball pocket, clearance selection and calculation formula needs to be changed accordingly. 2. Robot bearing key technology (1) thin-walled bearing precision clearance control technology. Industrial robot bearings require smooth operation, should have the right to start the friction torque, so the bearing production, assembly should have the right amount of negative clearance. Bearing a negative clearance is too large or too small will directly affect the bearing noise, vibration and life, because the robot with thin-walled bearings inside and outside the ring wall thickness is thin, the use of load and load measurement of clearance, easily lead to deformation , The amount of negative clearance is difficult to control, the need for special processing and assembly methods and processes, and the use of special assembly tools. (2) thin-walled angular contact ball bearing assembly height of the precise control. Robot compact structure, the installation space is accurate, requiring high rigidity of the assembly of the bearing high, and similar foreign assembly of the high rigidity control is also very strict. As the thin-walled angular contact ball bearing ring wall thickness is very small, easily deformed, the size of precision is difficult to precisely control, inner and outer ring and the rolling body is difficult to strictly control the size of matching size, resulting in assembly assembly after bearing high deviation is too large. Therefore, in order to achieve high precision control of the thin-wall angular contact ball bearing assembly, even to achieve the purpose of universal matching, bearing must be a special groove position design, grinding process formulation, precision matching, while increasing bearing bulge The amount of grinding process. (3) thin-walled bearing precision assembly technology. As the robot series of precision bearings thin wall thickness, poor stiffness, the use of common assembly methods and molds, in the heating assembly sleeve easily deformed. Therefore, to achieve precision assembly of thin-walled bearings to achieve the target of the finished product must be used for thin-walled bearing assembly size matching, assembly process development and special assembly molds and accessories, the matching of the bearing rings Strict grinding, the development of detailed and rigorous assembly process, and the development of special tools and accessories assembled sets to ensure that the accuracy of bearing assembly. (4) non-contact measurement technology of inner and outer diameters of thin-wall bearing rings. Thin wall bearing ring wall thickness is very thin, the need for precision cars and grinding to achieve the required tolerances, while thin-walled bearing profile parameters of the measurement accuracy is also very high, the use of traditional means of detection, such as standard bearing diameter measurement The use of D913 instruments, with 0.001 of the torsion spring table measurement, requires a certain force, but the table is difficult to accurately control the artificial force, a direct impact on thin-walled outer diameter measurement accuracy, can not meet the testing needs. Therefore, it is necessary to study the inner and outer diameter measurement methods of thin-wall bearing rings. Based on non-contact optical precision measurement technology, integrated motion computer vision, image processing, precision motion control and computer control and other related technologies, research and development of a thin Wall bearing ring outside the contour of special measuring instruments. |
