Research and Application of Robot Rotary Joint Bearing Grease

- Aug 12, 2019-

The robot can simulate the movement of people, mainly by the joint bearing. The general industrial robot mobile phone has 4 rotary pairs. Therefore, the lubrication of the sports pair is very important, which has a great influence on the working performance of the robot. The joints are divided into rotary joints, moving joints, cylindrical joints and ball joints.


The robot arm realizes predetermined rotation and movement of the member by the swivel pair and the moving pair. The rotary pair can be used with a joint bearing and a four-point contact ball bearing (semi-outer ring or double-half inner ring double-angle contact ball bearing). In addition to the thin-walled features of the general bearing, the bearing has the characteristics of no gap.


When the joint moves, under the action of external force, the base surface is stretched and deformed. When the rolling body rolls along the deformed base surface, the displacement of the rolling element within a full circle is slightly smaller than the circumference of the circumference. In addition, the deformation of the base surface is unevenly distributed along the contact arc, and a relative slip occurs between the rolling element and the base surface. In addition, there is rolling friction in the joint (sports pair)


Therefore, friction occurs in the joint (sports pair). There are intermittent, oscillating and continuous low-speed movements. If these bearings are improperly lubricated, causing excessive bearing wear, positional errors will occur. The work performed by the rolling element at the moving friction distance is numerically equal to the rolling friction. When the local pressure on the actual contact spot is high, two basic external friction processes are generated, which are due to the mutual intrusion of the microprotrusions. At the point of the run-in period, the microprotrusions are flattened and formed at the contact points as "weld joints" because the total area of the contact spots is very small and the pressure is also large. This paper analyzes the influence of the motion characteristics and friction characteristics of the robot's motion pair (section) on the working performance of the robot from the theory of tribology. The development and application of the special grease for the joint bearing of the robot motion sub-joint is proposed.


Industrial robot bearings mainly include two types of bearings for industrial robots, one is a thin-walled bearing with equal section, and the other is a crossed cylindrical roller bearing. There are also harmonic reducer bearings, linear bearings, joint bearings, etc., which are most suitable for the joint or rotating part of industrial robots, the rotary table of the machining center, the robot rotating part, and the precision rotating table. The joint bearing is a special type of plain bearing. Its structure is simpler than rolling bearings. It consists mainly of an inner ring with an outer spherical surface and an outer ring with an inner spherical surface. It can withstand large loads. According to its different types and structures, it can withstand radial loads and shafts. Combined load to load or radial and axial simultaneously. Joint bearings are generally used for low-speed oscillating motion (ie angular motion). Since the sliding surface is spherical, it can also be tilted in a certain range of angles (ie, aligning motion), and the support shaft is not concentric with the shaft hole. When the degree is large, it still works normally. Joint bearings can withstand large loads. Depending on their type and construction, it is possible to withstand radial loads, axial loads or combined loads of radial and axial forces. Since the outer surface of the inner ring is provided with a composite material, the bearing can be self-lubricated during operation. Generally used for low-speed oscillating motion, and low-speed rotation, it can also be tilted within a certain angle range. When the support shaft and the shaft housing hole are different, the normal operation can still be performed. Bisino B.GREASE-115-BN robot rotary joint bearing grease is made of high-performance polytetrafluoroethylene as a thickener and additive combined with special process. The rotational movement of the bearing creates friction between the rolling element and the cage due to the spin motion of the rolling elements. Due to repeated contact and squeezing of the rolling elements in contact with the surface microprotrusions. The grease containing Teflon is a paste which is filled in a small depression on the surface of the rolling direction of the rubbing direction. During the operation of the bearing, the PEFE particle ions gradually form an oil film. On the surface of each rolling element, the transfer film formed by the inner and outer rings directly participates in the friction process. During the rubbing process, it migrates to the friction surface, thereby improving the friction and wear properties of the friction surface. It is beneficial to improve the wear resistance of joint bearings. Bisino B.GREASE-115-BN robot rotary joint bearing grease consists of a fully synthetic mixed base oil, a special polymer as a thickener, and a solid nano-lubricating material, as well as rust inhibitors and abrasion resistance. Refined with a variety of additives, the product can form a reversible nano-lubricating layer on the lubricating surface, which can ensure the benign operation of the lubricating parts in a long period. It can micro-repair the lubrication surface, reduce vibration and reduce friction noise; it can ensure the lubrication work under the super load and impact load; it has strong adsorption and permeability, is not afraid of sand washing; strong physical and Chemical stability, can extend the fat-filling and fatliquoring cycle by 5 times.