What is a crossed roller bearing?
Crossed-roller bearings are bearings for high-precision applications whose dimensions conform to ISO dimension series 18 as per DIN 616. They comprise outer rings, inner rings, rolling elements and plastic spacers. The outer ring is split and is held together by three retaining rings.
Introduction of Crossed Roller Bearings
Their rollers are arranged at right angles to each other at intervals between the inner and outer wheels. They can bear loads from all directions at the same time (such as axial, thrust or momentum loads, etc.).
Because the rollers are in linear contact with the track surface, the possibility of elastic deformation of the bearing under load is very small. This type of bearing is widely used in such occasions as industrial automatic robots, working machinery and medical facilities, etc., where high rigidity, tightness and high speed are required to ensure accuracy.
In a crossed roller bearing, since the cylindrical rollers are arranged perpendicular to each other through spacers, a single crossed roller bearing can withstand loads in all directions, including radial load, axial load, and moment load. The size of the inner and outer rings is minimized, especially the ultra-thin type is a small size close to the limit, and has high rigidity, so it is most suitable for the joint part or rotating part of industrial robots, the rotary table of machining center, It is used for robot rotating parts, precision rotary tables, medical equipment, measuring instruments, IC manufacturing equipment, etc.
Features of Crossed Roller Bearings
For crossed roller bearings, since the divided inner ring or outer ring is installed with rollers and spacers, it is fixed with the crossed roller collar to prevent separation from each other, so it is necessary to install the crossed roller collar.
Simple. Since the rollers are arranged in a cross, only one set of Cross Roller Rings can withstand loads in all directions, and the rigidity is 3 to 4 times higher than that of conventional models. At the same time, since the inner ring or outer ring of the crossed roller bearing is divided into two structures, the bearing clearance can be adjusted, and even if a preload is applied, high-precision rotational motion can be obtained.
1.Excellent rotation accuracy
The internal structure of the crossed roller bearing adopts the rollers arranged at 90° perpendicular to each other.
There are spacers or spacers between the rollers, which can prevent the rollers from rubbing against each other due to the inclination of the rollers. In addition, there is no contact phenomenon or locking phenomenon of one side of the rollers; at the same time, because the inner and outer rings are divided structures, the gap can be adjusted, and even if a preload is applied, high-precision rotational motion can be obtained.
2. Simplified operation and installation
The outer ring or inner ring, which is divided into two parts, is fixed together after the rollers and cages are installed, so it is very easy to install.
3.Bear large axial and radial loads
Because the rollers are arranged perpendicular to each other on the 90° V-groove running surface by spacers.
4.Significantly save installation space
The size of the inner and outer rings of the crossed roller bearing is minimized, especially the ultra-thin structure is a small size close to the limit, and has high rigidity, so it is most suitable for the joint parts or rotating parts of industrial robots, and the rotation of machining centers. Widely used for worktables, manipulator rotating parts, precision rotary tables, medical instruments, measuring instruments, IC manufacturing equipment, etc.
5.High speed capability
6.Reduced shaft length and machining cost, limited change in geometry due to thermal expansion
7.Using nylon divider, low moment of inertia, low starting torque, easy to control angle indexing
8.Optimized pre-tightening force, high rigidity and high running accuracy of guide rollers
9.Carburized steel provides excellent impact resistance and surface wear resistance
10.Simple but well lubricated
Classification and Model Series of Domestic Crossed Cylindrical Roller Bearings
RB type (outer ring split type)
The RB series is the basic type of the crossed cylindrical roller bearing. The inner and outer rings are minimized in size. The structure is that the outer ring is a split type and the inner ring is an integral design. It is suitable for parts that require high rotation accuracy of the inner ring. .
RE type (inner ring split type)
The RE series model is a new type produced by the design concept of the XRB type, and the main dimensions are the same as the XRB type. Its structure is that the inner ring is a split type, and the outer ring is a one-piece design, which is suitable for parts requiring high rotation accuracy of the outer ring.
RU type (integrated inner and outer ring type)
The RU series model does not need a fixed flange and a support seat due to the machining of the mounting holes. In addition, since the integrated inner and outer ring structure with seat is adopted, installation has little effect on performance, so stable rotation accuracy and torque can be obtained. Can be used for outer and inner ring rotation.
RBC type (outer ring split type)
The RBC series model (corresponding to the CRBC series of IKO company) has a structure that the outer ring is a split type. The inner ring is an integral design, and a full complement roller bearing with a cage. It is suitable for parts that require high rotation precision of the inner ring.
CRBH type (inner and outer ring integrated type)
The inner and outer rings of the CRBH series are of one-piece structure for rotation of the outer and inner rings.
RA type (outer ring split, ultra-thin type)
The RA series model is a compact model that reduces the thickness of the inner and outer rings of the RB type to the limit. Ideal for applications requiring a lightweight, compact design, such as robotic and manipulator rotation.
SX type (outer ring split type)
The structure of the SX series is similar to the RB series. The outer ring is a two-part structure, connected by three spring snap rings, and the inner ring is designed in one piece, which is suitable for places requiring high rotation precision of the inner ring.
XRU08 type (integrated type of inner and outer rings)
The XSU08 series is similar to the RU series, and the inner and outer rings have been processed with mounting holes. So there is no need for a fixed flange and a support seat. Due to the integrated inner and outer ring structure with seat, installation has little effect on performance. So that stable rotation accuracy and torque can be obtained. Can be used for outer and inner ring rotation.
1 Thrust Angular Contact Ball Bearing
The contact angle of thrust angular contact ball bearings is generally 60°. Commonly used thrust angular contact ball bearings are generally bidirectional thrust angular contact ball bearings, which are mainly used for precision machine tool spindles. It has the advantages of high precision, good rigidity, low-temperature rise, high speed, and convenient assembly and disassembly.
2 deep groove ball bearing
Structurally, each ring of a deep groove ball bearing has a continuous groove-type raceway with a cross-section of approximately one-third of the equatorial circumference of the ball. Deep groove ball bearings are mainly used to bear radial loads, and can also bear specific axial loads. When the radial clearance of the rolling bearing increases. It has the properties of an angular contact ball bearing and can bear axial loads alternating in two directions. Compared with other types of bearings of the same size. This type of bearing has a small friction coefficient, high limit speed and high precision, and is the preferred bearing type for users when selecting models. Deep groove ball bearings have a simple structure and are easy to use. They are the type of bearing with the largest production volume and the widest application range.
3 thrust tapered roller bearing
Since the rolling elements in the thrust tapered roller bearing are tapered rollers, the rolling busbar and the raceway busbar of the washer both meet at a certain point on the axis of the bearing so that the rolling surface can form pure rolling and high limit speed. for thrust cylindrical roller bearings. Features: Thrust tapered roller bearings can withstand unidirectional axial loads. The type code of thrust tapered roller bearing is 90000 type.
Introduction to Crossed Cylindrical Roller Bearings
There are two types of crossed roller bearings, one is crossed cylindrical roller bearings, the other is crossed tapered roller bearings; crossed roller bearings have a long history of application abroad, but only recently in China. It has only entered the public’s vision for a few years, and it is widely used due to its own particularity and incomparable advantages over other bearings.
Main features of crossed roller bearings:
- It has excellent rotation accuracy. The internal structure of the crossed roller bearing adopts the rollers arranged at 90° perpendicular to each other (this is also the origin of the name of the crossed roller bearing). There are spacers or spacers between the rollers. Which can Prevent the rollers from tilting or grinding against each other, effectively preventing the increase of rotational torque. This crossed cylindrical roller bearing has been included in Kuaiyueyou. In addition, there will be no contact phenomenon or locking phenomenon of one side of the roller. At the same time, because the inner and outer rings of the standard crossed roller bearing are divided structures, the gap can be adjusted. Even if it is Pre-pressure can also be applied to obtain high-precision rotary motion.
Simplified operation and installation.
- The standard crossed roller bearing is divided into two parts of the outer ring or the inner ring. After the rollers and cages are installed, they are fixed together. During installation, they can be adjusted by fine-tuning the connecting bolts and fixing flanges. The ideal load state is reached, so the installation operation is very simple.
- Bearing large axial and radial loads Because the rollers are arranged perpendicular to each other on the 90° V-groove rolling surface through spacers. This design enables the crossed roller bearing to withstand large loads. Loads in all directions including radial load, axial load and moment load.
- The installation space is greatly saved. The size of the inner and outer rings of the crossed roller bearing is minimized. Especially the ultra-thin structure is a small size close to the limit, and has high rigidity. So it is most suitable for joint parts or rotating parts of industrial robots. The rotary table of the machining center, the rotating part of the manipulator. The precision rotary table, the medical instrument, the measuring instrument, the IC manufacturing device, etc. are widely used.
Application range of crossed roller bearings
Precision rotary indexing tables for machine tools. Vertical and horizontal boring machines, vertical grinding machines, rotary surface grinding machines, large gear hobbing machines, gun and radar rotary tables, large radio and optical telescopes, rotating cameras, steering pivots and continuous casting machines. Height-constrained pivot microscope stages, pole center pivots, rotary bogies, welding stands, rotary assembly jigs, industrial robots, precision rotary tables, medical instruments, metrology instruments, IC manufacturing equipment
What are Crossed roller bearing?
Crossed roller bearings are bearings for high-precision applications with dimensions in accordance with DIN 616, ISO size series 18. They are consist of an outer ring, an inner ring, a rolling element and a plastic spacer. The outer rings are separate and are held together by three retaining rings.
Due to the X arrangement of the cylindrical rollers. These bearings can withstand axial forces from both directions and radial forces. Overturning moment loads and any combination of loads by means of a single bearing position. Thus, designs involving two bearing positions can be reduced to one bearing position. Crossed roller bearings are very rigid, have high operational accuracy and provide normal clearance, low clearance or preload. The outer ring of the bearing can be easily fixed to the adjacent structure using clamping rings.
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