China High performance Bearing for Cement Industry

We are well aware of the harsh operating environment of cement equipment and the changing trend of the industry. We are willing to understand the business of our customers and strive to provide reliable and high-quality bearing products for each application environment. We cooperate with our customers to customize personalized friction management solutions for our customers. We take the initiative as the development idea, and actively establish cooperation with cement equipment manufacturers and cement plant maintenance team to improve productivity and minimize downtime.

 

Bearings used in cement equipment are mainly of the following:

— Spherical Roller Bearings

— Tapered roller bearing

— Cylindrical roller bearing

— Spherical plain bearing

— Insert bearing with housing

— Deep groove ball bearing

— Slewing ring

The vertical mill of industrial cement is not only suitable for the cement industry, but also for the grinding of medium hardness materials such as coal, coke, cement raw materials, gypsum, barite, phosphate rock, decomposition stone, kaolin, etc. in metallurgy, building materials, chemical industry, electric power and other industries. It integrates grinding, drying, grinding and powder selection, with small construction area, roll turning out, maintenance and other features.

According to these characteristics, we have developed a series of bearing products which can meet the working conditions. Among them, the grinding roller is the main part of rolling and grinding materials. In order to work in the drying gas of more than 180 degrees with large load rolling, and the particle size of the grinding material is large, the maximum can reach about 5% of the diameter of the grinding roller, generally 40-100 mm, so there is a large impact load. Through the optimization design of the bearing structure, the use of high-quality steel and proper adjustment of heat treatment process, the service life of the grinding roller bearing is increased to more than 40000 hours. The grinding disc is fixed on the output shaft of the reducer, and the upper part of the grinding disc is a material bed on which the material is crushed by four grinding rollers. Generally, the bearing of the grinding plate adopts the dynamic and static pressure bearing, but the cost is high and the processing is difficult. The coatmaster rotary table bearing processed by special technology has the characteristics of strong bearing capacity and simple installation. The reducer bearing can meet the requirements of large transmission ratio and large load.

In the harsh application environment of the cement industry, coatmaster’s full range of high-performance bearing solutions adopt the engineering technology independently developed by Timken Company in materials, surface processing, contact surface geometry and coating, which can help our customers reduce equipment design and The total cost of operation, in order to enhance competitiveness, so as to reflect the value of Timken products and the value-added for you. For the harsh environment, our high-performance bearings can:

  • improve bearing performance and prolong bearing life
  • Increase the power density, and the bearing capacity of high-performance bearing is higher under the same installation space
  • Reduce bearing replacement cost and equipment maintenance cost
  • increase equipment uptime and productivity
  • maximize value and improve bearing cost performance

  • crusher
  • grinder
  • vibrating screen
  • ball mill
  • cement rotary kiln
  • Supporting wheel
  • roller press

The operation of the above mechanical equipment is closely related to the selection and use of bearings. However, in the cement production process, due to the complex production conditions, many people have no idea about the selection and installation of bearings.

The cement production line is mainly composed of crushing and pre homogenization, raw material preparation homogenization, preheating and decomposition, cement clinker burning, cement grinding and packaging. Bearings mainly include roller press main shaft bearing, vertical mill roller bearing, vertical mill curved arm bearing, cement rotary kiln supporting wheel, retaining wheel and pinion bearing, ball mill main shaft bearing, crusher bearing, etc. Although there are many kinds of bearings, their main working characteristics are low speed and heavy load, large impact, so the bearing with high bearing capacity, impact resistance and high reliability is the only choice for enterprises.

In the process of cement production, the bearing life will be accelerated due to the influence of large dust, moisture, high temperature, vibration and other factors. The guarantee and extension of bearing life need to start from both ends, one is the production link, the other is the use link. Coatmaster thinks that the installation at the end of use is the most important. Coatmaster Technology Department provides guidance for bearing installation in cement plant to ensure the normal operation of bearing as the core hub.

China bearing for agricultural machinery

Recently, the problem of food shortage in the world is more and more worrying. In this regard, agricultural machinery that can achieve efficient and stable food production has become increasingly important. There are many kinds of agricultural machinery adapted to the use environment and crop types of various countries and regions.

Coatmaster’s agricultural machinery bearing, in a large number of agricultural machinery applications, the most representative is the tractor. The tractor is a kind of traction machine which is installed on the power department in front of and behind the car body to realize farming, sowing, fertilizing and spraying.

China Coatmaster bearings are used in gearbox, hub, engine and other parts of the tractor, and most of them are used under muddy water and heavy load conditions. In addition, the agricultural machinery used on the vast cultivated land in Europe and the United States is gradually developing towards large-scale, and the service conditions of bearings are becoming more stringent. Under such service conditions, customers put forward the requirements of both high reliability and high cost performance for bearings.

The mainly bearings used in Agricultural machinery

— Agricultural flanged disc harrow bearing

— Pillow block bearing

— Deep groove ball bearing

 

 

 

 

 

 

 

 

— Taper Roller Bearing

— Needle Roller Bearing

— Cylindrical Roller Bearing

— Spherical Plain Bearing

The annual demand for large and medium horsepower tractors is about 200,000, and the number of combine harvesters is 100,000. In addition, the ownership of all kinds of agricultural machinery is also increasing. It is estimated that by 2025, the ownership of large and medium horsepower tractors will be about 2.3 million, and the number of combine harvesters will be about 800,000. Bearing products for agricultural machinery OEM matching accounted for a large proportion. Therefore, the market demand of hydraulic and pneumatic seals for agricultural machinery matching and maintenance will increase greatly. Agricultural machinery products need a large number of pillow block bearing, cylindrical roller bearings, ball bearings, needle bearings, etc.

Because agricultural machinery is mostly used in muddy water environment and heavy load working conditions, it has higher requirements for foreign matter resistance and long life. In order to meet these requirements, coatmaster has developed agricultural machinery bearing with special seal, agricultural machinery bearing with special material heat treatment technology, agricultural machinery bearing with high purity and other products by using the design technology, material technology, tribology technology and manufacturing technology which are proud of in the world, realizing the unprecedented long life and foreign matter resistance.

In the future, Coatmaster will provide customers with bearing products with unique cutting-edge technology to meet customer needs.

Excellent sealing performance, maximum extension of service life of various agricultural machinery

  • award winning custom solutions for the most demanding application environments
  • environmentally friendly, maintenance free solutions that reduce labor, lubrication, and machine acquisition costs

Coatmaster ( China Bearing Manufacturer) is the market leader in the agricultural machinery industry in China, providing complete agricultural bearing solutions. Bearings for disc harrows, planters, harvesters and strappers perform well in the most hostile environments. The conditions of crops and pastures vary according to the geographical environment and seasons, from drought and abrasiveness to humidity and corrosiveness. In agricultural application, pollution is the main cause of bearing failure, and using coatmaster seal can provide the bearing with the best decontamination performance, thus extending its service life. Coatmaster can provide standard, industry recognized specifications, and support the development of unique solutions to meet special user requirements. Coatmaster has now launched products specially designed to meet the needs of the agricultural industry.

China bearing for Mining industry

No matter in the initial design stage or in the application industry, we have rich experience to provide bearing solutions. Mining equipment has been working in hard environment for a long time, carry heavy load, debris pollution, serious eccentricity, large-scale operation speed. The excellent quality of Chinese bearings ensures the continuous and stable operation of mining equipment in such a harsh environment, minimizes the cost input and economic loss of accessories caused by equipment maintenance, and ensures the safety of ground and underground construction.

Over the past years, we have provided specially designed high-performance Bearing for the application conditions of mining equipment, including tapered roller bearings, needle bearings, cylindrical roller bearings, spherical roller bearings and ball bearings. The bearing’s internal geometric design, surface treatment, roller and cage design can withstand heavy load and unpredictable load during production, and can resist debris and other pollutants. Our metallurgical knowledge and extensive experience in bearing manufacturing help our customers improve mining related solutions.

What you can get is not only a bearing, but also a comprehensive friction management solution. We comprehensively review your whole system and production objectives, and then recommend appropriate products and solutions to improve the operation time and high performance of moving parts. We have used different friction management technology in many occasions to solve the practical problems of mining operators and equipment maintenance.

China bearing for Metallurgical Industry

The most demanding working environment in the world requires the best bearing, which is rarely as harsh as the rolling mill, continuous casting machine, converter and other equipment in the metallurgical industry. These working conditions require the bearing to resist the adverse effects of high temperature, heavy load, water and dust. Over the years, in order to meet the requirements of harsh environment to adapt to extreme conditions, we have produced bearings for metallurgical industry with excellent quality, accuracy and innovative technology.

Our main types of metallurgical bearings are:

  1. Deep groove ball bearing
  2. Cylindrical roller bearing
  3. Self aligning roller bearing
  4. Angular contact ball bearing
  5. tapered roller bearing
  6. Thrust ball bearing
  7. Thrust roller bearing
  8. QJ four point contact ball bearing
  9. Slewing support slewing bearing
  10. Plummer block housing
  11. Carb toroidal roll bearings

In the metallurgical industry, we are not only a bearing manufacturer, but also a solution provider. With the development of product models and service types, we have the ability to provide customized solutions for our customers. Our products are also selected by the mill manufacturer as installed components. Idler Roller bearing is the heart of rolling mill. Our workroll bearing, back-up roll bearing  and thrust bearing can guarantee the continuous operation of the mill for 24 hours under extremely harsh environment.

In addition to Idler Roller bearings, we can also provide Continuous Caster bearings, converter trunnion bearings and other auxiliary equipment bearings. The bearing of continuous caster must be subject to constant erosion of high temperature, cooling water and dust. Our split cylinder, self-aligning roller bearing and standard sector bearing can provide excellent solutions for the application of continuous casting. The trunnion bearing of converter and the bearing of auxiliary equipment such as leveler, finisher, uncoiler, coiler, disc shear and conveying raceway ensure that we can provide customers with comprehensive bearing solutions.

Electrically insulated deep groove ball bearing

Electrically Insulated deep groove ball bearing is a kind of deep groove ball bearing which can prevent the current from passing through and has insulation performance. Its insulation performance is usually to process a layer of alumina coating on the outer ring or inner ring of the bearing with international advanced technology to withstand the voltage DC.

The insulated deep groove ball bearing is composed of inner ring, outer ring and rolling component. The rolling component includes steel ball and retainer. The outer surface of inner ring or outer ring of the bearing is provided with a ceramic insulating layer.

From the above description, it can be seen that the structure of insulated deep groove ball bearing and common deep groove ball bearing is the same, with the same size. All ferrules, retainers and steel balls are the same. Ferrules are made of high-quality bearing steel, and cages are designed with pressed steel and brass, as well as with nylon retainers for special purposes. The rolling elements has different designs of steel balls and ceramic balls, which we generally call It is a hybrid ceramic ball bearing. Both the deep groove ball bearing and the insulated deep groove ball bearing have two different designs of opening and sealing. There are two forms of deep groove ball bearing: oil lubrication and grease lubrication.

In addition, the Electrically insulated bearing also has the design of all ceramic bearing. The bearing rings and rolling elements are made of zirconia or silicon oxide. This kind of bearing has the characteristics of insulation, corrosion resistance and water resistance. All ceramic deep groove ball bearing, common deep groove ball bearing and insulated deep groove ball bearing can be selected according to the specific use of customers.

Electrically Insulated Deep groove ball bearing mainly bears radial load, but also can bear radial load and axial load at the same time. When it only bears radial load, the contact angle is zero. When the deep groove ball bearing has large radial clearance, it has the performance of angular contact bearing and can bear large axial load. The friction coefficient of the deep groove ball bearing is very small and the limit speed is very high.

Deep groove ball bearing is the most commonly used rolling bearing. Its structure is simple and easy to use. It is mainly used to bear radial load, but when the radial clearance of the bearing is increased, it has certain performance of angular contact ball bearing and can bear combined radial and axial load. When the speed is high and it is not suitable to use thrust ball bearing, it can also be used to bear pure axial load. Compared with other types of deep groove ball bearing with the same size, the friction coefficient of this kind of bearing is small and the limit speed is high. But it is not resistant to impact and is not suitable to bear heavy load.

The basic coating of insulated deep groove ball bearing can withstand voltage up to 1000V DC. And can supply 500v-3000v DC coating according to customer’s requirements. Its model representation method is the same as that of ordinary type bearing, with only some suffixes added. According to different cage and sealing ring, the reference international bearing code can be divided into:

— Insulated deep groove ball bearing

— Sealed Insulated deep groove ball bearing

— Hybrid ceramic ball bearing

— Ceramic ball bearing

Electrically Insulated deep groove ball bearings are widely used in automobiles, tractors, machine tools, motors, generators, high-voltage motors, water pumps, agricultural machinery, textile machinery and environments with special applications.

The insulated deep groove ball bearing manufacturer as follows

— SKF made in Austria

— FAG From Germany

— NTN and NSK made in Japan

CoatMaster Made In China

— NKE Made In Austria

FAG Current insulated bearings for traction motor

FAG Current insulated bearings can prevent the effect of stray current. Insulated bearing combines bearing function and insulation performance in the solution, so it is more cost-effective than other insulation methods.

With a unique coating process, a layer of aluminum oxide is coated on the surface of the inner or outer ring of the bearing, so that it has the insulation ability and is not affected by high temperature, moisture and chemicals. The performance and running accuracy of the bearing are the same as that of the standard uninsulated bearing, and no additional installation measures are required.

Technical data

Car unit

Wheel arrangement Bo’2’Bo’

Traction adhesion 65 %

Track gauge 1,000 mm

Distance between wheel pairs 1,800 mm

Vehicle length over buffers 31,480 mm

Max. weight when full 56 t.

Max. axle load 8.3 t.

Max. speed 60 km/h

Wheel diameter (new/worn off) 600/520 mm

Min. track radius14.5 m

Floor height 300 mm

Low floor component 100 %

Traction motor

Traction motors 4 x 100 Kw

(nominal operating point)

Max. speed 4000 min-1

Traction motor inverters 2 IGBT pulse

width modulated inverters

Gear ratio 5.4444

Bearing arrangement

The traction motors are equipped with an FAG NU215E.TVP2.J20A insulated cylindrical roller bearing at the drive end (floating bearing) and an FAG 6215M.C3.J20A insulated deep groove ball bearing at the opposite end (locating bearing).

Both bearings are protected against damage from current sparkover by an oxide ceramic coating (> 0.2 mm thick).

Bearing life The traction motor bearings were designed for a theoretical mileage of more than 2 million kilometers. Drive unit The Combino drive unit consists of: motor, brake disk, spring-loaded brake, motor-gear coupling, bevel gearing, quill shaft, wheel-gear coupling. Each wheel is driven via a quill shaft with two rubbermetal couplings. Current insulation/coating, in general Current insulated bearings prevent damage from current sparkover in the event of potential gradients between the rotor and stator of an electric motor. The oxide ceramic coating, which was applied by means of plasma spraying, features a hardness of > 2000 HV. It is wear-resistant and a good heat conductor. With the J20A coating, the disruptive voltage with direct current is > 1000 V

How to improve the precision of China made bearings?

High precision bearings belongs to high performance bearing. The high performance we mentioned mainly requires high speed and high load capacity, long service life and reliability, low vibration noise and low friction torque, and can withstand some extreme construction conditions (such as high and low temperature, corrosion), etc. High performance bearings are mainly used in aviation and aerospace, as well as high-speed railway, precision machine tools and high-end automobiles. High precision bearings generally involve “high technology” and “high quality”.

After more than 60 years of reform and opening up, China’s bearing industry is growing. At present, there are no significant deficiencies in the types, varieties and specifications of bearing products, basically with a relatively complete product line. However, the product structure is not very balanced. The production capacity of middle and low-end ordinary products has been in excess, while the market of high-end products is still dominated by foreign famous brand products. So far, There are significant breakthrough has been made in some bearings technology just like the railway bearings.

For the current situation of the technical quality level of China’s bearing products, we can summarize the situation that the quality is not as good as that of the top quality and the high-end bearing is not as skilled as the SKF, FAG, INA, NSK, NTN brand.

Ordinary bearings are relatively mature in technology, and there is basically no restriction of entry threshold. No matter large enterprises or small enterprises are able to carry out production of the bearings, so the competition is mainly based on price, so domestic bearings constitute the main body of the market whether in the domestic market or in the export of foreign exports. However, even for some ordinary bearings with low technical content, there is still a big gap between domestic bearings and foreign famous brand products in terms of their own accuracy consistency, performance stability, life reliability and other quality levels. In the current transformation and upgrading tasks of our national bearing industry, the most urgent need is to carry out the product Adjust the structure. Among them, the focus is to complete the strategic layout in the field of high-precision bearings, so that they can achieve effective breakthroughs in the short term, and occupy the main position at the highest point of technology. This is not only the basic demand for the sustainable development of the bearing industry, but also the objective requirement for the national economy and the security of national defense. The key technology of high-precision bearing manufacturing is that the bearing is a kind of precision mechanical product, so the technology is the key point in the bearing manufacturing process.

1. Equipment is the prerequisite for the implementation of Technology

For example, grinding is the most critical final machining step in bearing ring manufacturing. The main equipments used are special grinding machine and super finishing machine. First of all, we must meet the basic requirements of high precision and high efficiency. In the past, the bearing grinder was mainly a semi-automatic and automatic machine controlled by electro-hydraulic. With the development trend of technology progress, CNC machine tools dominate the bearing grinder and super finishing machine tools. The CNC grinding machine composed of automatic production line is not only suitable for the mass continuous production of ordinary bearings, but also very flexible, and can cooperate with the production of a variety of special bearings. Therefore, CNC has become the main choice for many bearing enterprises to upgrade the processing equipment technology. Some types of bearing rings have simple geometric structure and low precision requirements, so it is OK to adopt PLC economic numerical control system; some types of bearing rings have high requirements, such as the raceway must be processed into the logarithmic shape of “convexity”. General or high-end CNC system shall be used to meet the requirements.

2. The bottleneck restricting the processing quality of high-precision bearings

For high-end bearings, in addition to the gap between raw materials and heat treatment, the accuracy and related problems are mainly reflected in the consistency of parts grinding, especially in batch processing.

(1) A typical example of precision bearings is angular contact ball bearings for machine tool spindles. For example, P4 or higher bearing rings have a large difference in machining accuracy. A good company usually has a one-time treatment qualification rate of about 80%. The matching rate was 60%. Some types of bearings (such as tapered roller bearings of wind turbine shafts) are also difficult to maintain quality above P4.

(2) The high-precision grade I and grade 0 rollers used for cylindrical roller bearings and taper roller bearings with P4 accuracy and above cannot be mass produced, and the processing quality of grade II or III rollers will fluctuate.

(3) The dimensional stability of parts can not be well controlled and guaranteed. Grinding stresses and deformations are too large and machining defects such as grinding burns and cracks occur sometimes.

3.Key technologies and measures to break the bottleneck

(1) Use machine tools with high accuracy, stability and reliability. For some bearing rings with complex shapes, it is necessary to use the grinder with full-function CNC system to directly call the function so that it can be controlled and interpolated in time; for internal surface grinding, the high-speed motorized spindle is used, while for external surface grinding, the high-speed motorized hydrostatic grinding wheel spindle is mainly used to complete the high-speed grinding; for semi closed loop and closed-loop servo system, it is necessary to use the grinder with high-speed control and interpolation It can control and complete precise micro feed and compensation. The feed resolution can imagine 0.25 μ m or reach 0.1 μ m, and the accuracy of repeated positioning can meet 1 μ m or reach 0.5 μ m. It uses high-precision, rigidity, wear-resistant ball screws, guide rails and other moving parts. It uses a bed with sufficient aging stability and relatively good vibration absorption effect, which is higher The precision grinder needs to use granite bed with strong vibration attenuation ability and relatively low thermal expansion coefficient.

(2) The active measurement method is used for grinding dimension control, with control accuracy of 3 μm or more to 1 μM. The servo motor is used to drive and control the wheel dresser, reduce the interval of wheel dressing, and improve the quality of wheel dressing; or the diamond wheel and CBN wheel with good shape retention are used to ensure the consistency of shape accuracy in batch machining.

(3) Through forging, finishing or precision cold rolling, the grinding allowance can be reduced, and additional tempering and cold treatment can be fully carried out between each working procedure to eliminate grinding stress and avoid excessive feed to produce defects such as grinding burns and cracks, so as to improve machining accuracy and surface quality.

(4) Pay attention to improve the manufacturing level of key parts such as rolling element and cage. Especially for high-precision cylindrical roller and tapered roller, the use of automatic production line. High precision rollers must be completely stable and aged.

(5) Realize the control of the environment condition of precision and ultra precision machining, and give up the long-term practice of the open workshop or general air-conditioning plant of bearing production. According to the requirements of constant temperature and humidity, vibration isolation and cleaning, the environmental facilities in the processing area shall be constructed or reconstructed strictly.

(6) Fully develop the characteristics of “Mastering and inheriting” in the production of precision parts, strengthen the skill training and experience accumulation of operators, strictly enforce the process flow and process discipline, strengthen the quality assurance system, match the “software” with the “hardware”, and improve the performance of excellent hardware.

In addition to the relatively low overall technical level, the two main problems of China bearing in the field of high-precision bearings are raw materials and manufacturing technology. In the use of manufacturing technology, equipment and technology are required to have a certain breakthrough, and also need to use sophisticated equipment and advanced technology to guarantee the high accuracy and retention of high-end bearings, so that their own high-performance and stability, as well as long life and reliability and other characteristics can be guaranteed and realized. The well-known Bearing Companies in the world regard equipment and technology as one of their own “technical treasures”, which also shows that manufacturing technology is the core competitiveness of enterprises for development. At present, our country’s bearing industry is actively undergoing transformation and upgrading, so we must focus on manufacturing technology as the main direction of attack, and complete key breakthroughs in the field of high-end bearings, hoping to make our country develop from a big bearing country to a strong bearing country as soon as possible.

Electrically insulated bearings for electric motors

Electric Motor bearing, also known as motor bearing, is a kind of special bearing specially applied to motor. The bearing used in the motor is a part supporting the shaft, which can guide the rotation of the shaft, and also can bear the idle parts on the shaft. The concept of the bearing is very broad. There are four types of bearings commonly used in motor, namely rolling bearing, sliding bearing, joint bearing and oil bearing. The most common motor bearing is rolling bearing, that is the bearing with rolling element. All the motor bearings will produce strong current in operation, which will cause corrosion to the bearings, thus affecting the service life of the bearings. The design and application of electrically insulated bearings solve this problem well.

Electrically Insulated bearings can prevent the effect of stray current. Insulated bearing combines bearing function and insulation performance in the solution, so it is more cost-effective than other insulation methods.

With a unique coating process, a layer of aluminum oxide is coated on the surface of the inner or outer ring of the bearing, so that it has the insulation ability and is not affected by high temperature, moisture and chemicals. The performance and running accuracy of the bearing are the same as that of the standard uninsulated bearing, and no additional installation measures are required.

According to the specific application of the electrically insulated bearings, they can be many kinds of bearing design, electrically insulated ball bearing, insulated roller bearings, insulated bearing with inner ring coated, insulated bearing with outer ring coated, as well as rolling element coated design.

There are some of the top bearing manufacturer can produce electrically insulated bearings above mentioned.

1. SKF electrically insulated bearings

INSOCOAT bearings with coated outer ring Bearings with an electrically insulating coating on the external surfaces of the outer ring are the most common INSOCOAT bearings. They are identified by the suffix VL0241. Outer ring coated INSOCOAT bearings are recommended for medium size motors, that use 6215, 6313 size bearings and larger. For applications where smaller bearings are used, SKF recommends hybrid deep groove ball bearings.

INSOCOAT bearings with coated inner ring Bearings with an electrically insulating coating on the external surfaces of the inner ring provide enhanced protection against electric current damage. The enhanced protection results from the increased impedance due to the smaller coated surface area. Bearings with a coated inner ring are identified by the suffix VL2071 and are recommended for larger size motors (typically from bearing sizes 6226, 6324 sizes and larger), or other applications where the bearings risk being subjected to high shaft voltages.

VL0241 Electrical resistance: min. 50 MW, breakdown voltage: max. operating voltage 1 000 V DC.

VL0246 Electrical resistance: > 150 MW, breakdown voltage: max. operating voltage 3 000 V DC.

VL2071 Electrical resistance: min. 50 MW, breakdown voltage: max. operating voltage 1 000 V DC.

VL2074 Electrical resistance: > 150 MW, breakdown voltage: max. operating voltage 2 000 V DC

2.FAG Current insulating bearing

The current-insulating bearings include all rolling bearings that give insulation against current passage. Coated bearings, in which either the inner ring or outer ring has a ceramic coating, are current-insulated bearings. The ceramic layer gives insulation against current passage. Hybrid bearings in which the rolling elements are made from ceramic also have a current-insulating effect. In this case, the rolling elements prevent current passage.

The coatings are subjected to 100% quality inspection and ensure a dielectric breakdown strength of at least:

■ J20AB as insulation up to 1000 VDC

■ J20AA, J20C as insulation up to 3 000 VDC

■ J20B as insulation up to 500 VDC.

Below this voltage, the insulating layer allows only very small flows of current through the bearing. In principle, a current-insulating bearing can be integrated as a parallel circuit between resistance and capacitance, the Ohm resistance should be as high as possible and the capacitance as low as possible.

3. NTN  insulated Coated bearing

Electrical pitting often occurs in bearings used in electrical equipment, such as motors and power generators, as a result of current leakage. An electrical current present near a bearing can flow to the inside of the bearing, causing sparks that damage the rolling contact surface, ultimately leading to bearing failure. This electrical pitting and can be prevented with coated bearings or ceramic hybrid bearings.

NTN’s MEGAOHM™ Series of insulated bearings has been specifically designed to counteract electrical pitting. These bearings are available in both ceramic and resin versions that are suited to a variety of applications. Coating the outer ring of the bearing provides a barrier (capable of resisting at least 100 Megaohms at 500 VDC) against any stray currents that would pass through the bearing.

MEGAOHM™ Series bearings are featured as OEM equipment on wind turbine generators, traction motors for railway cars, and variable speed electric motors in wastewater treatment facilities.

CERAMIC HYBRID BEARINGS

For especially problematic applications, NTN offers ceramic hybrid bearings. Using conventional steel inner and outer rings, silicon nitride rolling elements provide excellent electrical insulation while reducing rotating mass and improving heat dissipation.

4. NKE electrically insulated rolling bearings

NKE electrically insulated rolling bearings reliably prevent current discharge. 

NKE provides bearings with oxide ceramic insulating layers on the bearing ring. Applied with plasma technology, the insulation has a guaranteed breakdown resistance of at least 1000V AC or DC. Two variants are available:

  • SQ77: Insulation on the outer ring
  • SQ77E: Insulation on the inner ring

Product range

SQ77 (insulated outer ring)

  • Cylindrical roller bearings 
    • Design variants: NJ, NU, NUP
    • Dimension series: 210-230, 310-330
    • Cages: brass and polyamide
    • Radial clearance groups: C0, C3, C4
  • Deep groove ball bearings 
    • Dimension series: 6212-6226; 6312-6326
    • Cages: brass
    • Radial clearance groups: C3, C4
  • Other types and SQ77E (insulated inner ring) upon request

5. CoatMaster lectrically insulated bearings

CoatMaster, as the Top Brand of China Bearing manufacturer, focus on reserch & develop Electrically Insulated Bearing, it can provide various types of insulated bearings

  1. Electrically insulated deep groove ball bearing
  2. Electrically insulated angular contact ball bearing
  3. Electrically insulated cylindrical roller bearing
  4. Electrically insulated tapered roller bearing
  5. Electrically insulated spherical roller bearing
  6. Electrically insulated spherical roller thrust bearing
  7. Electrically insulated linear motion bearing
  8. Inner or outer ring insulated bearing with oxide coating
  9. Hybrid bearing with electric insulating ceramic rolling element

Electrically insulated Bearing is mainly used for motor products. Its use depends on the power supply status of the motor. There is no high-frequency voltage and current component in the normal power supply network. Generally, insulated bearing is not used only for large high-voltage motor, such as rules above 400kW type motor. But now the frequency conversion power supply, because the power quality contains a lot of high-frequency components, resulting in the increase of motor shaft current, so this problem should be considered in the standardization of more than 400kW, and even the smallest motor should also be installed with insulated bearings according to the use conditions, such as electric vehicles, electric rail locomotives, etc. the main motor used is generally about 1000kW, so the electric insulated bearings must be used, or it should be used the insulates the structure to keep the shaft current from flowing.

SKF INSOCOAT electrically insulated rolling bearings

SKF insocoat electrically insulated rolling bearing are widely used in many kinds of industry, Motors, generators and related equipment are in danger when current passes through the bearings. This not only damages the contact surfaces of the rolling elements and raceways in the bearing (electrical corrosion), but also quickly degrades the grease. Another additional risk comes from high-frequency currents in motors and generators, which can form a loop through the parasitic capacitance inherent in the device. Increased risk of damage if frequency converter is used.

SKF insocoat Electrically insulated rolling bearings:

— Designed to prevent current from flowing through the bearing

— The outer surface of their inner or outer ring is coated with an insulated alumina layer, and a sophisticated plasma spray process is applied to obtain an excellent quality finish.

— A very cost-effective solution compared to other insulation methods

Reliability is an essential requirement for modern bearings with longer intervals between maintenance.
For example, they must be robust enough to operate in electrical equipment with modern AC technology.

The passage of electric current through rolling bearings can lead to damage in a relatively short period of time. Small craters caused by electric current passage which have been tolerated occasionally in the past are no longer acceptable. SKF, as a consequence, has developed the INSOCOAT bearing range (fig. 1). These bearings have special coated outer rings with an electrically-insulated layer for a breakdown voltage up to 1,000 V.

To ensure smooth, trouble-free operation, it is necessary to prevent the bearing from electric current passage. The contact areas between housing, outer ring, rolling elements, inner ring and shaft can act as electric contacts. The resulting arcs – characterised by very high temperatures similar to that produced by melting and welding processes – will damage rolling elements as well as raceways of bearing rings. Typical damage is characterised by craters (fig. 2) and false brinelling.

The risk for damage to bearings can occur when transient voltages exceed 0.5V or the electric current flow is more than 0.1A/mm2 (related to the contact area of rolling elements). Also, electric current does not normally flow evenly through several bearings connected together, for example. Electric current flow tends to be concentrated in only one bearing.

To overcome this problem SKF has developed INSOCOAT bearings. Leading manufacturers of electrical machinery confirm that the use of electrically-insulated bearings offers the most economical solution when compared to other protective measures.

Applications

Typical applications of the new bearing are in traction motor protection. Potential cases are:

  • case 1: where electric current could flow from the housing to the shaft. In this case all bearings have to be electrically insulated (fig. 3)
  • case 2: for electric current flow inside the rotor, normally caused by asymmetrical electric motors. Here protection of only one side of the bearing arrangement is necessary. Mainly the smaller bearing, situated on the non-drive side, is selected for electrical insulation (fig. 4)
  • case 3: in wheel bearings for low floor tramcars (fig. 5)

Bearing design

The insulating coating on the outer ring of the INSOCOAT bearing is made from aluminium oxide and applied using plasma spraying technology. SKF has carried out extensive research and development in this area and is pursuing further improvement of the process. The latest phase of the development is the ability to handle a 1,000V dielectric breakdown voltage.

Design characteristics of the bearing include:

  • ISO standard dimensions and tolerances
  • Interchangeability with non-insulated bearing types
  • Suitability for all common housing types
  • Dielectric breakdown voltage optional up to 500V or 1,000V.
  • Coating thickness of about 0.05 mm
  • Durability of coating
  • High thermal stability

Common suffixes used for INSOCOAT bearings are:
VL024 and VA309 breakdown voltage to 500V and VL0241 and VA3091 breakdown voltage up to 1,000V. VA309 and VA3091 are applied to bearings for traction motor applications.

To ease mounting in case of tight housing fits, it is recommended that the housing bore is provided with an additional chamfer of 15° on the side at which mounting should commence. The ceramic coating has sufficient hardness and adhesive power to resist damage during mounting if all the bearings are handled with reasonable care.

In principle, electrically-insulated bearings can be of any type. Most common bearing types include cylindrical roller bearings and deep groove ball bearings with outside diameters larger than 75 mm for traction motor designs, stationary electric motors (medium and large types), generators and special applications including submersible pumps. Also electrically-insulated taper roller bearings could be used as wheel bearings for tram and suspension tube bearings for electric railway vehicles.

Series of electrically insulated bearing

The standard scope of supply of insulated bearings includes the most common sizes and variants of bearings:

  • Single-row deep groove ball bearings
  • Single-row cylindrical roller bearings

In addition to the standard classification, SKF can also provide special INSOCOAT bearings and bearing units with complex ring geometries such as:

— Flanged tapered roller bearings

— Traction motor bearing unit

CoatMaster as the China Bearing Manufacturer, it focus on Research & develop the Electrically Insulated Bearing since 2009, Through 10 years learning from SKF, FAG, NSK Such top quality Bearing manufacturer, CoatMaster Mastered the core technology of insulation technology and the quality of Electrically insulated bearing reached the world class quality level and save the cost for the insulated bearings end-user. its quality are proved by our regular customers on the market.

It not only can produce the top quality Insulated deep groove ball bearings, insulated cylindrical roller bearing, insulated tapered roller bearings, but also the inuslated spherical roller bearing, insulated spherical roller thrust bearings, insulated angular contact ball bearings, insulated linear motion bearing, insulated self-aliging ball bearings, Hybrid ceramic bearing etc. CoatMaster would like to supply the complete bearing industry solution for Electrical Motor of Railways,Industrial electric motors & generators,Wind energy,Construction,Industrial pumps.

Top 10 bearing manufacturers in China

As we all know, more than 70% of the world bearing market share is shared by the top ten multinational bearing group companies. Among them, the United States, which accounts for 23% of the global market, 21% of the European Union, and 19% of Japan, are basically dominated by five companies such as Japan’s NSK, Sweden’s SKF, Germany’s FAG, and the United States Timken. At the same time, the high-end market of the world’s bearing industry is monopolized by the above-mentioned enterprises, while the middle and low-end market is mainly concentrated in China.

Chinese bearings are favored by foreign markets because of their high quality and low price. At present, Chinese bearings are exported to the United States, Europe, South America, India, the Middle East, Africa, Russia and other major countries and regions. Different market groups. Relatively speaking, many importers don’t have a deep understanding of Chinese bearings. Let’s talk about the Top 10 bearing manufacturers in China first.

In 2020, China’s policy orientation will continue to guide capital investment in key areas of the bearing industry. With the top 10 bearing manufacturers in China as the leader, the bearing industry will be tilted towards high-precision, high-tech content and high value-added products, accelerating the bearing industry. upgrade. Driven by the development of various fields such as rail transit, medical equipment, new energy, aerospace, and automotive light weighting, the level of China’s high-end bearing casting industry will be significantly improved. As the focus of global manufacturing shifts to China, the development of China’s high-end bearing industry has a strong impetus, and the requirements for domestic high-end bearing manufacturers have become higher and higher. At present, China’s bearing casting industry must focus on improving product grades and reducing manufacturing costs to achieve a strategic transition from “big” to “strong”.

No.1 of China Bearing manufacturer

Wafangdian Bearing Co., Ltd—  ZWZ

Wafangdian Bearing Group Co., Ltd. was founded in 1938. It is the birthplace of China’s bearing industry and ranks eighth in the world bearing industry. ZWZ’s leading products are supporting bearings for major technical equipment, rail transportation bearings, and automotive vehicle bearings. Wind power new energy bearings, precision machine tools and precision ball screws, precision large castings. ZWZ more than 18,000 kinds of bearing products all have independent intellectual property rights, accounting for 26% of all conventional bearing varieties in the world, and at the rate of nearly 1,000 new products being developed each year, they meet market demand, and new products account for about 45% of sales revenue. Products are exported to more than 100 countries and regions in the world. The company has passed ISO9000, ISO14001, QS9000 and ISO18000 certifications.

No. 2 of China Bearing manufacturer

Luoyang Bearing Corp. (Group)- LYC

Luoyang Bearing Corp. (Group)-LYC was founded in 1954 and is one of the 156 key projects in China during the First Five-Year Plan period.

LYC has passed ISO9001, ISO14001, TS16949, CRCC, OHSAS18001, American ARR, French AS9100C, German GL and other domestic and foreign authoritative organizations certification. The product series cover nine types and more than 20,000 kinds. The product size ranges from 10mm inner diameter to 13.5 m. With core technologies such as rail vehicle bearings and thin-wall bearings for major equipment, the products are widely used in wind power generation, rail transportation, automobiles and motorcycles, mining and metallurgy, engineering machinery, machine tool motors, industrial gearboxes, medical equipment, port machinery ships, etc. field.

No.3 of China Bearing manufacturer

Harbin bearing group co. ltd. — HRB

HRB bearings are one of the three major bearing production bases in China. From 2007 to the present, after restructuring and reorganization, separation of main and auxiliary,  HRB bearings currently have 3388 main production equipment, an annual production capacity of 80 million sets, and sales revenue of 1.2 billion. A bearing product system with more than 7,000 specifications and varieties of ten major types, with railway passenger car speed-up bearings, precision machine tool spindle bearings, and mine metallurgical bearings as the leading products, has been formed.

The railway speed-up passenger car bearing developed by HRB has been confirmed as a fixed-point manufacturer by the Ministry of Railways. The railway bearing has become the backbone product of HRB. The YRT series precision CNC machine tool spindle bearing developed by HRB has filled the domestic gap and achieved localization.

No. 4 of China Bearing manufacturer

Renben Group Co., Ltd  — C & U

C & U Group was founded in 1984. It is a group company with bearing manufacturing as its leading industry. It also owns RenBen mechanical and electrical trade and a full-scale chain of convenience stores. It currently has 137 member companies, more than 20,000 employees, and assets of 11.09 billion. In 2018, it realized sales income of 17.13 billion yuan and completed profit and tax of 1.21 billion yuan.

C & U Group is the vanguard of China’s bearing industry. Through investment, mergers and acquisitions, technological transformation, etc., it has now formed seven major bearing production bases in Wenzhou, Hangzhou, Wuxi, Shanghai, Nanchong, Wuhu, and Huangshi. It has 65 bearing finished products with an inner diameter of 1.0mm. There are more than 30,000 kinds of bearings in the range of 4000mm in outer diameter. In 2018, 1.2 billion sets of bearings were produced.

Through the implementation of agency system and chain monopoly operation, C & U has established 69 bearing marketing companies and 130 bearing sales offices and bearing stores in central cities across the country, forming a national sales chain network of bearing products, and in the United States Trading companies in Japan and Germany.

No.5

Luoyang Bearing Science and Technology Co., Ltd– ZYS

Luoyang Bearing Science and Technology Co., Ltd-ZYS is a high-tech enterprise focusing on the development of “high, precise, sharp, special” bearing products for key hosts and defense construction in various fields of the national economy. Its predecessor, Luoyang Bearing Research Institute, was established. In 1958, it was the only national first-class comprehensive research institute in China’s bearing industry. In 1999, it entered China National Machinery Industry Corporation and was transformed into a science and technology enterprise.

The company focuses on the development of high-performance bearing products for key hosts of the national economy and national defense, and mass-produces various types of high-end equipment bearings and components with an inner diameter of 0.6mm to an outer diameter of 6.8 meters. The main business is the research, development, production and sales of precision thin-wall special bearings, high-speed machine tool spindles, bearing special equipment and testing instruments, bearing test machines and special bearing materials. The products are widely used in aerospace, ship weapons, machine tools , Wind power generation, mining metallurgy, petrochemicals, medical equipment, automobiles and rail transportation, engineering machinery, intelligent manufacturing services and other fields.

No.6

Zhejiang Tianma Bearing Group Limited company– TMB

Zhejiang Tianma Bearing Group Limited company has 30 years of development history. The company’s leading products include ten types of bearings with a total of more than 8,000 varieties.

Products by type are: cylindrical roller bearings (single row, double row, four row), deep groove ball bearings, tapered roller bearings, spherical roller bearings, spherical ball bearings, angular contact ball bearings (single row, double row) , Thrust roller bearings, thrust ball bearings, non-standard bearings.

According to the application fields: aerospace bearings, military bearings, railway freight cars, passenger cars and rail transportation bearings, automotive bearings (new energy), wind power bearings, marine bearings, machine tool bearings, mechanical bearings, metallurgical rolling mill bearings, motor bearings, etc.

The new materials independently developed by the product are used for high-end bearing products, and have won the favor of domestic and foreign users due to the long life and high quality of the products. Among them, cylindrical roller bearings, railway bearings, wind power bearings, rolling mill bearings, etc. have always enjoyed a high reputation in the bearing industry Popularity.

No.7

Xibei Bearing Co., Ltd.– NXZ

Baota Industrial Co., Ltd. (formerly Northwest Bearing Co., Ltd.), formerly known as the Northwest Bearing Factory, is the largest specialized bearing manufacturer in the western part of the country. In 1996, it was restructured and listed, becoming the first stock listed company in the Chinese bearing industry.

The company has a national-level enterprise technology center, which develops more than 200 new products every year. The R & D of oil drilling bearings 30228 / 630Q has won the National Quality Gold Award. It is at the leading domestic level in product development and manufacturing processes in the field of large special bearings. The product was successfully applied to the Shenzhou-5 and Shenzhou-6 launch monitoring devices. The company has more than 500 kinds of products to fill the gap in the country, and nearly a thousand kinds have reached the international advanced level.

No.8

Xiangyang Automobile Bearing Co., Ltd. ZXY

ZXY was founded in 1968 and listed on the Shenzhen Stock Exchange in 1996. ZXY has an engineering technology center specializing in the development and application of new automotive bearing products, new technologies. In addition to automotive bearings, it also designs machinery, agricultural machinery, appliances and fans. Bearing products.

The company’s technological research and development capabilities are in an absolute leading position in the domestic automotive bearing industry. A number of technologies such as reinforced tapered roller bearings, full complement cylindrical roller bearings, automotive air conditioning compressor bearings and clutch bearing simulation testers have international patents. ZXY is now Formed a system of supporting bearings for various models of heavy, medium, light, miniature, passenger cars, etc. ZXY brand bearings enjoy a high reputation in the auto parts market, and their products are exported to Europe, America and Southeast Asian countries and regions.

No. 9

Fujian Longxi Bearing group corporation limited — LS

Fujian Longxi Bearing group corporation limited is a modern state-owned listed company that produces and sells spherical plain bearings, tapered roller bearings, rolling functional components and high-end mechanical components. The company has an annual output of 15 million sets of spherical bearings and 8 million automotive tapered roller bearings. The production capacity of 2.6 million pieces of maintenance-free cross shafts and 20 million pieces of shaft sleeves.

The company’s leading products, the number of joint bearing varieties, production and sales rank first in the world. It is widely used in various types of machinery and equipment in the national economy industry and national key projects such as the Shenzhou series, Chang’e series, the National Astronomical Observatory FAST project, Tiangong, large aircraft, Shanghai Center Building And a large number of export to more than 40 industrial developed countries and regions such as Europe, America and Asia. The company can develop both AS and EN standard aviation articulated bearings, as well as various non-standard aviation articulated bearings. Through the most authoritative experimental organization in the field of articulated bearings, the most stringent A standard bearings in the laboratory of the US Navy Aviation Command (NAVAIR) The certification is the only domestic enterprise that has passed certification. The 8 types of aviation joint bearings with more than 6,000 specifications developed by the company are listed in the US government procurement qualified product catalog (QPL-AS81820).

No.10

Qianchao Bearing

Wanxiang Group Corporation–QC Bearing

In 1994, Wanxiang Qianchao (000559) was listed and traded on the Shenzhen Stock Exchange. Universal joints bearing, transmission shafts, brakes, fuel burners, exhaust systems and other products were recognized as Chinese famous brand products. In 2005, the “Qianchao” trademark was recognized as a well-known brand. Trademark, Wanxiang Qianchao has been committed to the research and development and manufacturing of auto parts. Products from parts to components to system integration, professional production, thin-walled serialization, modular supply, products cover universal joints, wheel hub units, Bearings, automotive chassis and suspension systems, braking systems, transmission systems, exhaust systems, fuel tanks, construction machinery components and other automotive system components and assemblies, is one of the largest independent automotive component suppliers in China.

No.11

XRB-ZWA BEARING INDUSTRY CO.,LIMITED — CoatMaster

CoatMaster was founded in 2007 and mainly produces bearings for electric motors. According to market demand, CoatMaster started to research and produce insulated bearings 7 years ago. Now it can produce and provide a full range of Electrically insulated bearings:

Insulated deep groove ball bearings

Insulated cylindrical roller bearings

Insulated tapered roller bearings

Insulated spherical roller bearings

Insulated thrust roller bearings

Insulated angular contact ball bearings

Insulated self-aligning ball bearings

Insulated linear bearings

Hybrid ceramic ball bearings

CoatMaster product can completely replace SKF, FAG, NSK, NKE and other world-renowned brands of insulated bearings.


China Bearing
has accumulated a lot of production technology and experience since 1938. Now China Bearing has been widely used in military, aerospace, automotive, machinery, agriculture, wind power and other fields, and can be used in some high-precision fields Comparing with bearings of SKF, FAG, NSK and other brands, the bearings made in China are divided into:

1. Deep groove ball bearing

2. Self-aligning ball bearings

3. Cylindrical roller bearing

4. Spherical roller bearings

5. Needle Roller bearing

6. Angular contact ball bearings

7. Tapered roller bearing

8. Thrust ball bearings

9. Thrust roller bearings

10. CARB toroidal bearing

11. Full complement cylindrical roller bearings

12. Cross roller bearings/Slewing Bearing

13. Linear motion bearings and slides

14. Self-lubricating bearings

15. Pillow block bearing

16. Spherical plain bearing and rod end

17. Cross shaft bearing

18. Universal joint bearing

19. Bearing Housings

20. Cam follower Bearing

21. Thin section Bearing


Amount of bearing export During 2012-2018

Note: 轴承出口金额 means Amount of bearing export

(千美元) means Thousand USD$ Dollars

Quantity of Bearing export During 2012-2018

Note: 轴承出口数量 Quantity of Bearing export

(万套) means 10 Thousand pcs

At the same time, China Bearing can produce different materials such as bearing steel, stainless steel, plastic, ceramic, carbon steel, etc. According to the application, it can provide high temperature, low temperature, wear resistance, corrosion resistance, waterproof, high load bearing, high speed, high precision, ultra thin wall, insulation. And other special-purpose bearings, the export volume and export value of bearings have gradually increased in recent years. We are happy to share more information about Chinese bearing products and the Chinese market with foreign bearing-related Customers.