The progress of the new era has driven the rapid development of China’s economy, giving it even greater momentum. The bearing industry has developed rapidly in recent years, and the precision requirements for bearings in various industries have also been increasing. For example, with the development of the robotics industry, miniaturization and light weighting will be the trend for robot bearings.
Thin section bearings and crossed cylindrical roller bearings are widely used in intelligent manufacturing and can effectively save space, reduce weight, reduce friction, and improve rotational accuracy, making miniaturization and lightweighting of the mainframe possible. Thin-walled section bearings and crossed cylindrical roller bearings are the two main types of bearings used in industrial robots. In addition, there are also harmonic reducers, linear bearings, and hinge bearings.
Industrial robot bearings are one of its key supporting components and are most suitable for industrial robot joint or rotating parts, mechanical machining center rotating worktables, mechanical arm rotating parts, precision rotating worktables, medical equipment, measuring instruments, IC manufacturing equipment, and other widely used applications.
Features of industrial robot bearings:
They can withstand comprehensive loads in axial, radial, and tilting directions; thin bearings; high rotational positioning accuracy. Any bearing that can meet these design requirements can be used in industrial robot arms, rotating joints, chassis, and other parts.
I. Crossed roller bearings
Characteristics of crossed roller bearings: Crossed roller bearings have cylindrical rollers or tapered rollers arranged perpendicularly to each other on V-shaped rolling surfaces at a 90-degree angle through isolating blocks. Therefore, crossed roller bearings can withstand loads in multiple directions such as radial, axial, and moment loads. The size of the inner and outer rings is miniaturized, and the ultra-thin form is close to the limit of small size, and it has high rigidity. The precision can reach P5, P4, P2 level. Therefore, it is suitable for industrial robot joint and rotating parts, mechanical machining center rotating tables, precision rotating worktables, medical equipment, calculators, military industry, IC manufacturing equipment, and other equipment.
1. Excellent rotational accuracy:
The internal structure of crossed roller bearings adopts rollers arranged perpendicularly to each other at 90 degrees, and the rollers are equipped with spacer retainers or isolating blocks to prevent the rollers from tilting or wearing against each other, effectively preventing the increase of rotational torque. In addition, there will be no contact or locking of one side of the rollers. At the same time, because the inner and outer rings are segmented structures, the clearance can be adjusted, and even with preloading, high-precision rotational motion can be obtained.
2. Simplified operation and installation:
The outer or inner ring, which is divided into two parts, is fixed together after the rollers and retainers are installed, so the operation is very simple during installation.
3. Can bear large axial and radial loads:
Because the rollers are arranged perpendicularly to each other on the V-shaped rolling surface at 90 degrees through the spacer retainer, this design allows crossed roller bearings to withstand loads in all directions such as large radial loads, axial loads, and moment loads.
4. Significantly save installation space:
The size of the inner and outer rings of crossed roller bearings is minimized, especially the ultra-thin structure is close to the limit of small size, and it has high rigidity, so it is most suitable for industrial robot joints or rotating parts, mechanical machining center rotating worktables, mechanical arm rotating parts, precision rotating worktables, medical equipment, measuring instruments, IC manufacturing equipment, and other widely used applications.
Types of crossed roller bearings:
1. RB type crossed roller bearing (outer ring split type, inner ring for rotation)
This series is the basic type of crossed cylindrical roller bearings, and the inner and outer ring sizes are minimized. Its structure is that the outer ring is split type, and the inner ring is integral design, suitable for parts with high requirements for inner ring rotational accuracy.
2. RE type (inner ring split type, outer ring for rotation)
This series is a new type of design concept derived from the RB type, with main dimensions the same as the RB type. Its structure is that the inner ring is split type, and the outer ring is integral design, suitable for parts with high requirements for outer ring rotational accuracy.
3. RU Type (Integrated Inner and Outer Ring Type)
This series has pre-machined mounting holes, eliminating the need for fixing flanges and support seats. Additionally, the integrated inner and outer ring structure with a retainer seat has virtually no impact on performance during installation, thus achieving stable rotational accuracy and torque. It can be used for both outer and inner ring rotation.
4.CRB Type (Outer Ring Split Type, Inner Ring for Rotation)
The structure of this series is that the outer ring is split type, and the inner ring is integral design without a retainer. It is suitable for parts with high requirements for inner ring rotational accuracy.
CRBC Type (Outer Ring Split Type, Inner Ring for Rotation)
The structure of this series is that the outer ring is split type, and the inner ring is integral design with a retainer. It is suitable for parts with high requirements for inner ring rotational accuracy.
CRBH Type (Integrated Inner and Outer Ring Type)
This series has an integrated inner and outer ring structure and can be used for both outer and inner ring rotation.
5.RA Type (Outer Ring Split Type, Inner Ring for Rotation)
This series is a compact type that reduces the thickness of the RB type inner and outer rings to the limit. It is suitable for parts that require lightweight and compact design, such as industrial robot and manipulator rotating parts.
6.RA-C Type (Single Split Type)
This type has the same main dimensions as the RA type. Because it has a single gap structure in the outer ring, the outer ring also has high rigidity, so it can also be used for outer ring rotation.
7.XR/JXR Type (Crossed Tapered Roller Bearings)
This type of bearing has two sets of raceways and rollers arranged at right angles to each other with interleaved rollers. The cross-tapered roller can withstand high overturning moments and is suitable for machine tools, including vertical boring and grinding machine tables, precision rotary tables for machine tools, large gear hobbing machines, turntables, industrial robots, etc.
II. Thin Section Bearings
Thin section bearings, also known as thin-walled bearings, have high precision, are very quiet, and have strong load-bearing capacity. They can be deep groove ball bearings, four-point contact bearings, or angular contact ball bearings, and the cross-section of thin-walled section bearings is mostly square. Even with larger shaft diameters and bearing bores, the cross-section remains the same. These bearings are therefore called equal section bearings.
Thin ection bearings come in seven open series and five sealed series. The open series has three types: radial contact type C, angular contact type A, and four-point contact type X. The advantages of thin section bearings are that they achieve an extremely thin bearing section and product miniaturization and weight reduction. The variety of products expands their scope of application.
Features of thin section bearings:
To obtain low friction torque, high rigidity, and good rotational accuracy, small diameter steel balls are used. The use of hollow shafts ensures lightweight and wiring space. The thin-walled 6700 and 6800 series have various dust cover forms, flange forms, stainless steel forms, and wide forms, with a complete variety.
Applications of thin section bearings:
Stepper motors, medical equipment, office equipment, testing instruments, speed reducers/variable speed devices, industrial robots, optical/imaging equipment, rotary encoders.
