Roller bearing, one of the two members of the class of rolling, or so-called antifriction, bearings (the other member of the class is the Ball Bearing). Like a ball bearing, a roller bearing has two grooved tracks, or races, but the balls are replaced by rollers. The rollers may be cylinders or truncated cones. Only radial loads (i.e., loads perpendicular to the axis of rotation) can be carried when the rollers are cylindrical, but with conical rollers both radial and thrust, or axial, loads (i.e., ones parallel to the axis of rotation) can be carried. A needle bearing has cylindrical rollers that are relatively slender and completely fill the space between the races; in many cases the inner race is dispensed with. Because there is line contact between a roller and the races, while in a ball bearing there is point contact, in a given space a roller bearing can carry a greater radial load than a ball bearing.
Roller bearings are used in all main shaft and auxiliary drive shaft applications to support pure radial load, and allow for axial shaft elongation due to temperature changes with no additional load effect on the bearing. They are usually located at the ends of the turbine and compressor shafts and are often mounted in a housing, but separated from it by a layer of pressurized oil known as a squeeze film damper. Roller Bearing,Self-Aligning Roller Bearing,Double Row Roller Bearing,Neddle Roller Bearing Shijiazhuang Longshu Mechanical & Electrical Equipment Trading Co., Ltd. , https://www.longsbearings.com
In many cases, instead of having a separate inner race for roller bearings, the [inner race" is an integral part of the shaft or stub shaft. This reduces complexity, weight, and build-up of concentricity tolerances. Overall, this is cost effective, but the cost of replacement or repair is likely to be higher than for separate inner races.
2012 global solar photovoltaic market confusion
The industry judges that the global solar photovoltaic market is still in a period of stagnation in 2012. The low spot price makes most manufacturers bitter, and the policy direction of developed economies has not greatly boosted the market, and the policy effects of emerging economies will take time. As a result, the market is still in the dormant phase of the previous outbreak. The price, market, and technology continue to develop, which will open the gap between manufacturers. According to a consulting organization in the industry, 2012 will be a year in which the global solar photovoltaic industry interface will face the difficult challenges. According to the current development, from the perspective of the policy, the current market policy trend is mainly based on the total amount of control and the reduction of subsidies. Emerging market policies have been released, but they still have time to brew; on the other hand, the current price trend of the industrial chain, the spot transaction price from the middle wafer to the module field is still low, compared with the actual production cost, most manufacturers They are all in a state of biting their teeth. It is estimated that the global solar photovoltaic market installation volume will reach 19GW in 2011, but the overall inventory of the industry (including finished products and semi-finished products) will be as high as 10GW, so the supply and demand situation of the industrial chain is still in a serious oversupply. The main reason is that the demand in the European market is affected by the policy adjustment. The demand in Italy, Germany, the United Kingdom and other countries is declining. On the other hand, the demand in the Asian market is encouraged by the policy, but like China, Japan, Malaysia. Demand in 2012, such as Thailand, is still growing at a small rate, and it is estimated that the market will see strong growth until 2013. In addition, although the North American and Indian markets have attracted attention, there are still problems in these two markets that need to be resolved. From the US market, the CashGrant bill will expire at the end of 2011 and will be replaced by the TaxCredit Act in 2012. The TaxCredit Act has limited power to push the market forward, making the US market in chaos unclear in 2012. (The CashGrant Act and the TaxCredit Act are editors of the U.S. Subsidy Act for the Solar Energy Industry.) In the Indian market, although the implementation of the National Solar Plan has given the Indian market a huge potential demand, the central and local government’s implementation efficiency and financial status In addition, the implementation of the local self-made rate will become an uncertain factor affecting the future development of the Indian market. Finally, in terms of price, the above mentioned mid-range products are currently in an oversold condition, which makes the management of related manufacturers face great pressure. From the analysis of "Solar Photovoltaic Cost per Cycle (LCOE) Review", system cost is mainly determined by module cost, BOS (Balance of System) cost, and system performance. The “Solar Photovoltaic Per-Electricity Cost (LCOE) Review†study was conducted by a scholar at Michigan University of Technology and two scholars at Queens University in Kingston, Ontario. In terms of module cost, as the upstream polysilicon production capacity continues to open, the future module cost will return to health, but there will be no further decline in price in the short term. However, in terms of BOS, prices such as solar inverters and EPCs are still stable. Compared with the module cost, the current market conditions have been reflected, and the future BOS price will be the focus of adjustment. In addition to the cost adjustment, the future system efficiency improvement is also the focus of current manufacturers' research and development. The current demand for high-efficiency products continues to increase, reflecting this development. Looking ahead, the development of N-type Mono and Mono-like related products and technologies is worthy of attention. Influenced by the triple impact of price, market and technology evolution, 2012 will be a year in which the global solar photovoltaic industry companies have opened the gap. In the future, manufacturers that cannot gain an advantage in price and technology will be forced to be merged by large companies or eliminated by the market. Manufacturers who can survive this competition can share the sweet fruits of the market taking off again.