Views: 125 Author: Site Editor Publish Time: 2022-09-14 Origin: Site
Crossed roller bearings are a new type of bearing with its special structural features and advantages. Both theoretical research and production technology are quite mature
In the design and application of the bearing, the bearing capacity and service life of the bearing must be considered.
In the crossed roller bearings, because the cylindrical rollers are arranged perpendicular to each other on the 90° V-groove rolling surface through the spacer block, the crossed roller bearings can bear radial load, axial load and moment loads in multiple directions.
The size of the inner and outer rings is miniaturized, and the ultra-thin form is close to the limit of small size, and has high rigidity, so it is most suitable for joint parts and rotating parts of industrial robots, rotary tables of machining centers, manipulator rotating parts,
Equipment such as precision rotary tables, medical equipment, calculators, and IC manufacturing equipment.
Rotation accuracy: There are spacers between the vertically arranged rollers in the bearing, which prevents the inclination of the rollers and the mutual friction between the rollers and reduces the rotational torque.
In addition, compared with the previous use of steel cages, there is no edge stress concentration or locking of the rollers.
At the same time, since the inner ring or outer ring is divided into two parts, the bearing clearance can be adjusted, and even if a preload is applied, it can rotate smoothly with high precision.
Compared with bearings of other structures, the biggest difference between this type of bearing is that the cylindrical rollers are arranged perpendicular to each other on the V-groove rolling surface of 90°, and the rollers are separated by a spacer block.
In the internal arrangement of the crossed roller bearings, two adjacent rollers are arranged in a cross, and the axes of all the rollers with the same arrangement direction intersect with the center line of the bearing's rotation at one point.
The intersection of the two sets of roller axes arranged in opposite directions and the bearing rotation center line is symmetrical with respect to the plane where the roller center is located.
Such a structure can allow the bearing to withstand radial loads, axial loads and overturning moment loads in all directions.
1) High rotation accuracy
The spacer blocks are placed between the cross-arranged rollers, which can reduce the bending moment and the increase of the friction moment caused by the friction bow between the rollers.
Compared with traditional bearings using steel cages, crossed roller bearings do not cause one-sided contact and extrusion of the rollers. Therefore, even if the bearing is preloaded, the bearing can still rotate stably. In addition, the bearing has a negative clearance and can reciprocate within 360° to achieve precise positioning.
2) Increased stiffness
Compared to double row thin-walled angular contact ball bearings, crossed roller bearings can support loads in all directions with three to four times more rigidity than conventional bearing types.
3) Large bearing capacity
① Compared with the traditional steel cage, the cross roller spacer provides support for the entire length of the rollers, so that the rollers have a longer effective contact length, thereby greatly improving the bearing capacity.
② The load-bearing area where the rollers of traditional bearings contact the inner and outer rings is asymmetrical with respect to the axis of the rollers.
The greater the load, the greater the torque generated, resulting in contact between the end faces, resulting in frictional resistance, hindering rotation and accelerating wear.
The bearing area of the rollers of the crossed roller bearing in contact with the inner and outer rings is symmetrical with respect to the axis of the rollers
4) Effectively reduce the axial dimension.
The axial displacement when using crossed roller bearings is 1/3~1/2 less than when using other bearings, thus greatly reducing the cost.
The divided inner ring or outer ring cannot be separated after being fixed with bolts and nuts, and can be directly installed into the bearing seat for use.
At the same time, if the spacer block in the bearing is assembled incorrectly, it will have a great impact on the rotation performance and the force of the rolling element, so please do not disassemble the bearing casually.
1. The seams of the inner ring or outer ring sometimes deviate somewhat. Before installing the bearing housing, loosen the bolts that fix the inner ring or outer ring, correct it with a plastic hammer, and then install it.
2. When installing or disassembling, please do not apply external force to the connecting bolts.
3. Please pay attention to the dimensional tolerance of the installation parts, so that the side pressing flange can press the inner ring or the outer ring from the side.
1. The mounting point shall be carried out on the mounting part to remove dirt and confirm whether the burrs of the parts have been removed.
2. Since it is a thin-walled bearing inserted into the bearing or shaft, it is easy to tilt when inserting.
Please use a plastic hammer to find the level, while tapping evenly in the circumferential direction, and insert it little by little until it can be confirmed by sound.
Until the contact surfaces are completely abutted.
3. Installation of side compression flange
(1) After placing the side compression flange in place, shake it back and forth several times in the circumferential direction to adjust the position of the mounting bolts.
(2) Install the compression bolt. When hand-tightening the bolts, make sure that the boltholes do not become difficult to screw in due to the deviation of the boltholes.
(3) The tightening of the compression bolts can be divided into 3 to 4 stages from temporary tightening to formal tightening, and they are repeatedly tightened in the order on the diagonal.
When tightening the compression bolts of the two-split inner or outer ring, the two-split parts can be corrected by turning the integral outer or inner ring a little during the tightening process.
