Linear bearing is a linear motion system, which is used for linear stroke and cylindrical shaft. Because the bearing ball contacts with the bearing jacket point, the steel ball rolls with the minimum friction resistance, so the linear bearing has small friction and is relatively stable. It does not change with the bearing speed, and can obtain a stable linear motion with high sensitivity and high precision. The consumption of linear bearing also has its limitations. The most important thing is that the impact load capacity of the bearing is poor, and the bearing capacity is also poor. Secondly, the linear bearing has large vibration and noise when moving at high speed. The automatic selection of linear bearing is included. Linear bearings are widely used in sliding parts of precision machine tools, textile machinery, food packaging machinery, printing machinery and other industrial machinery.

Since the bearing ball is in contact with the bearing point, the service load is small. The steel ball rotates with minimal friction resistance, so as to obtain high-precision and stable motion.

Plastic linear bearing is a linear motion system with self-lubricating characteristics. The biggest difference between plastic linear bearing and metal linear bearing is that metal linear bearing is rolling friction, and there is point contact between bearing and cylindrical shaft, so it is suitable for low load and high-speed motion; The plastic linear bearing is sliding friction, and there is surface contact between the bearing and the cylindrical shaft, so it is suitable for medium and low speed movement under high load.

features

Linear bearing is used with quenched linear transmission shaft. A system of infinite linear motion. Because of the point contact between the load ball and the quenched transmission shaft, the allowable load is small, but when moving in a straight line, the friction resistance is the smallest, the precision is high and the movement is fast.

There are no special requirements for the matching shaft of plastic linear bearing; It can bear more load than metal bearing, but the movement between bearing and shaft is sliding friction, so the movement speed of plastic linear bearing is limited to a certain extent; The motion resistance is greater than that of metal linear bearing; However, its motion noise is lower than that of metal linear bearing, especially in the case of medium and high speed, the noise of plastic linear bearing has little influence with speed. The plastic linear bearing is allowed to be used in dusty occasions because of its internal chip removal groove design. The dust is automatically brought out of the friction surface of the bearing body from the chip removal groove during movement; Plastic linear bearings also allow cleaning during use. The internal sliding film made of special materials can even be used for long-term operation in liquid.

classification

(1) Standard type, clearance adjusting linear bearing, open linear bearing, extended linear bearing, general linear bearing

(2) The flange type can be divided into straight flange type, elliptical flange type and circular flange type.

According to specification and system:

It is divided into two series, LM and LME series Its code LM series is used in Asia, Southeast Asian countries, Japan, South Korea, China and so on. Taking the metric dimension as the standard, the outer diameter tolerance of the matched linear shaft is generally H7. LME series are mostly used in Europe, the United States, Germany, Italy and other regions. The standard is British dimension, and metric dimension is also available. The outer diameter tolerance of linear shaft is generally G6. The structural characteristics of the two series are roughly the same except for different dimensions and different aperture tolerances.

By shape:

1: Straight cylinder type (the shape is like a cylinder, which is generally installed with snap ring, and is used in occasions with small installation size)

2: Flange type (there is a mounting flange at the end or in the middle, which can be installed with screws. The flange is generally divided into round, square and trimming types)

3: Open type (the shape is like a straight cylinder, with axial slit on the surface. It is used for occasions requiring gap adjustment, divided into large opening and small opening)

By performance:

1: General type (use for general performance requirements)

2: Super type (occasions with long service life and high load performance requirements)

purpose

Linear bearings are more and more widely used in precision equipment or special machinery industries such as electronic equipment, food machinery, packaging machinery, medical machinery, printing machinery, textile machinery, machinery, instruments, robots, tool machinery, CNC machine tools, automobiles and digital three-dimensional coordinate measurement equipment.

Clearance

The inner and outer diameters of linear bearing adjustment type and open type bearings shall be measured before the cutting. There will be some elastic deformation after the cutting. The matching clearance shall be measured in the bearing seat (the situation of steel retainer bearing and KH bearing is similar). The adjustment direction of the bearing seat with adjustable clearance shall be perpendicular to the cutting direction of the bearing to ensure uniform clearance. The structural characteristics of the linear bearing can not make rotational movement, and it is required to have good guidance. Therefore, the linear bearing is generally used in a combination of two shafts + four sets of bearings or two shafts + two sets of extended bearings. The two shafts shall be installed straightly. After the whole combination assembly, The transmission mechanism can only be installed when pushing and pulling by hand. The transmission power should be enough to overcome the bearing friction resistance. The friction resistance of linear bearing is approximately one thousandth of the working load.

curing

Maintenance of metal linear bearing: lubrication and friction: inject anti-corrosion oil into the linear bearing. If grease is used for lubrication, first remove the anti-corrosion oil with kerosene or organic solvent, and then add grease after air drying. (lithium soap grease with viscosity mark N0.2 is recommended.) If the anti-corrosion oil does not need to be removed when lubricating with oil, the lubricating oil with ISO viscosity grade vg15-100 can be selected according to the temperature change Shaft lubrication can be supplied from the oil supply pipe or from the oil hole on the outer bearing seat. Since the sealing ring will scrape off the lubricating oil, oil lubrication is not suitable for bearings with sealing rings without holes.

Maintenance of plastic linear bearing: since the sliding film inside the plastic linear bearing is made of self-lubricating plastic, it does not need additional oil supply and maintenance during use; Moreover, because the plastic linear bearing has a chip removal groove, even if the bearing or shaft is full of dust, there is no need to maintain, and the dust will be automatically brought out of the chip removal groove during movement; Only when the sliding film is worn and fails, the internal sliding film can be replaced directly; Maintenance is very convenient.

management

(1) After disassembling each part of linear motion bearing series, foreign matters may enter or adversely affect the assembly accuracy of each part. Please do not disassemble.

(2) Falling or knocking of linear bushing may cause damage, please pay attention. When the product is impacted, even if the appearance is not damaged, the function may still be damaged. Please pay attention.

lubrication

(1) Please wipe the antirust oil carefully and seal it with lubricant before use.

(2) Please avoid mixing lubricants with different properties.

Linear guide bearing

A groove or ridge made of metal or other material that can bear, fix, guide and reduce the friction of mobile devices or equipment.

Longitudinal groove or ridge on the surface of guide rail, which is used to guide and fix machine parts, special equipment, instruments, etc. The application of guide rail in our daily life is also very common, such as the sliding slot of sliding door, train track and so on.