What types of bearing do industrial robots use?
Industrial robot bearings, as one of the key components of industrial robots, mainly include two types of bearings for industrial robots, one is a uniform cross-section thin-walled bearing, and the other is a cross cylindrical roller bearing. There are also harmonic reducer bearings, linear bearings, joint bearings, etc., but mainly the first two bearings.
The key technology of industrial robot bearings
The development of modern industrial robots tends to be lightweight. Bearings must be installed in a limited space and must be small in size and light in weight, that is, lightweight. But at the same time, the robot's high load, high rotation accuracy, high running stability, high positioning speed, high repeat positioning accuracy, long life, and high reliability performance require that the supporting robot bearings must have high load carrying capacity, high precision and high performance. Stiffness, low friction torque, long life, high reliability performance.
Detailed description of industrial robot bearings
1. Thin-walled constant-section bearings
Different from ordinary bearings, the cross section of each series of uniform section thin-walled bearings is mostly square, and the size is designed as a fixed value (see Figure 1): the cross section size in the same series is unchanged, it does not vary with the inner diameter size Increase and increase, so it is called equal section thin-walled bearings. Constant cross-section thin-walled ball bearings include thin-wall four-point contact ball bearing series, thin-wall angular contact ball bearing series and thin-wall deep groove ball bearing series. They are mostly used in the waist, elbow, and wrist of industrial robots, which require small cross-sectional dimensions. , Restricted parts. In the case of the same inner diameter size, thin-walled constant-section ball bearings have more steel balls than standard rolling bearings, so the internal force distribution of the bearing is improved, the elastic deformation of the contact between the steel ball and the raceway is reduced, and the bearing performance is improved. Carrying capacity.
2. Thin-walled cross roller bearings
The internal structure of the thin-walled cross cylindrical roller bearing adopts the rollers in a 90° mutually perpendicular arrangement. A single bearing can bear the combined action of radial force, bidirectional axial force and overturning moment at the same time. Spacers are installed between the rollers. Or the spacer block can prevent the rollers from tilting or the mutual rubbing between the rollers, effectively preventing the friction torque from increasing. In addition, the structure of the rollers arranged vertically and crosswise can avoid the locking phenomenon of the rollers; at the same time, because the inner and outer rings of the bearing are divided into a structure, the gap is adjustable, and even if pressure is applied, higher rotation accuracy can be obtained. Cross roller bearings are widely used in industrial robot waist rotation, articulated robot shoulders, arms, wrists and other rotating parts due to their light composite structure, high rotation accuracy, good rigidity, and stable friction torque.
4. Special bearing for harmonic reducer
Harmonic reducer is a kind of controllable elastic deformation of the flexspline by the wave generator, and the controllable elastic deformation of the flexible bearing is used to transmit motion and power. It is characterized by compact structure, high motion accuracy, large transmission ratio, and versatile use. For small and medium torque robot joints.
Harmonic reducer bearings can be divided into two categories: outer ring separated, inner ring integral CSF/CSG series harmonic reducer bearings, and inner and outer ring integral SHF/SHG series harmonic reducer bearings. The rolling elements of the harmonic reducer bearing are cylindrical rollers, which are distributed in V-shaped raceways arranged vertically at 90 degrees to each other. The structural characteristics of the harmonic reducer bearing enable a harmonic reducer bearing to simultaneously bear axial load, radial load and overturning moment and other directions of the load, and has high rigidity, rotation accuracy and composite load capacity; Robot harmonic reducer bearings also belong to the cross-roller bearing series. The bearing has high precision, flexible operation, small clearance, and small error; compact in appearance, the bearing has its own mounting hole, which is convenient for customers to install directly, and is suitable for various types of harmonics. Wave reducer. This type of bearing accounts for about 35% of China's industrial robot bearing market. And it is growing very fast.
CSF/CSG series harmonic reducer special crossed roller bearings are slightly different in structure from ordinary crossed roller bearings. The basic structure is similar. It adopts a split outer ring and an integral structure of the inner ring. Compared with standard crossed roller bearings , There are many mounting holes on the inner and outer ring, especially the inner ring. There are generally three levels of mounting threaded holes with different sizes and numbers from the outside to the inside. This is the biggest difference in appearance from the basic cross roller bearing. The materials are all made of GCr15 bearing steel, the heat treatment of the outer ring adopts the overall quenching process, and the inner ring adopts the high-frequency quenching process of the raceway surface. This is the biggest difference compared with the ordinary cross roller bearing process; the harmonic reducer uses a cross The smoothness and accuracy of the running friction torque of the roller bearing have a direct impact on the tooth meshing force and the running stability of the harmonic reducer, and it directly affects the service life of the harmonic reducer. Therefore, the special cross for the harmonic reducer The quality of the roller bearing directly determines the use effect and life of the harmonic reducer.
SHF/SHG series
The special cross roller bearing for harmonic reducer, its outer ring and inner ring are of integral structure, installation has no influence on performance, can obtain stable rotation accuracy (up to 0.002mm) and friction torque; suitable for SHF/SHG Series, CSD series harmonic reducer.
SHD series
The special cross roller bearing for harmonic reducer, the outer ring and inner ring are also integral structure, but the inner ring and the rigid wheel of the harmonic reducer are integrated, which further reduces the thickness and weight of the harmonic reducer. Special materials and heat treatment process make it have excellent performance, suitable for SHD series harmonic reducer.
Flexible bearing
It is one of the core components of the harmonic reducer. The requirement of high reduction ratio is achieved through the elastic deformation of the flexible bearing, and the life of the harmonic reducer also depends largely on the life of the flexible bearing. The flexible bearing changes continuously with the elastic deformation of the flexible wheel during operation, and it not only bears the cyclic stress load, but also bears the alternating stress load.
Luoyang Yujie Industry &Trade Co.Ltd located in Luoyang City, one of the main heavy industrial bases in China. We specialize in the production of bearings, nonstandard machinery parts, machine tools.
For the bearings, we can offer cross roller bearing, harmonic bearing,slewing bearing, YRT bearing, thin section bearing, ball screw bearing, deep groove ball bearing, etc. For the nonstandard machine parts, we can produce gears, shafts, sprockets, molds, rollers, pulley, mining machine parts, etc as per customer drawing and requirements. For the machine tools, we offer CNC vertical machine center, CNC horizontal lathe, CNC gantry boring and milling machine, CNC floor type boring, and milling machine.
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