Bearing ring grinding super processing technology and development ( A)

1. Preface as machinery manufacturing industry, the industry foundation is in the direction of the high precision, high efficiency, intelligent and flexible development. Grinding, ultra lapping processing ( 'Super grinding processing') Tend to be the ultimate mechanical products processing, its machining quality directly affect the product quality and performance. As machinery industrial base, in the production of one of the bearings, the ferrule grinding of ultra precision machining is decided to ring parts and the whole bearing the main link, which on the surface of the rolling mill processing, is affecting the service life of bearing and the main steps of bearing vibration damping noise reduction. Has always been super grinding processing, therefore, is a key technology in the field of bearing manufacturing technology and core technology. Bearing industry abroad, in the '60 s has formed a stable ferrule grinding processing technological process and basic method, namely: the double face grinding - — Centerless external cylindrical grinding - — Groove cut into the centerless grinding - — Raceway lapping processing. In addition to the special bearing structure, several processes, require additional ring all is according to the process of mass production of processing. For decades, the process is not a fundamental change, but this does not mean that no bearing manufacturing technology development. In a nutshell, the '60 s just building and development of the 'double - — Centerless cylindrical - — Cut into the ground - — Ultra lapping 'this technological process, and the corresponding was born into a series of cuts centerless grinder and ultra lapping machine tools, precision parts processing to 3 ~ 5 um, single processing time (13 ~ 18 s Small and medium size) 。 Is mainly used in the 70 s 60 m/s high speed grinding, control is used in great quantities in the grinding machine grinding technology and control, is characterized by integrated circuit of the electronic control technology of digital control technology is widely used, so as to improve the stability of the grinding machine and process, parts machining accuracy reaches 1 ~ 3 um, 10 ~ 12 s parts processing time. Since the 80 s, the technology and equipment of the machining accuracy is not problem, the main development direction is on the premise of stable quality, the pursuit of higher efficiency, more convenient adjustment and manufacturing system of numerical control and automation. 2. Bearing ring in bearing production of grinding, grinding labor accounts for about 60% of the total labor, the grinding machine used number about 60% of all metal cutting machine tool, grinding the cost of more than 15% of the cost of the bearing. For high precision bearings, grinding of the larger proportion. In addition, is the most complex, the machining process of grinding on the understanding is still the most inadequate. This complexity, displays in: the required performance indicators more and higher accuracy; Processing and forming mechanism of more complex, many factors affecting machining precision; Processing parameters on-line detection difficult. Therefore, for the bearing grinding, one of the key working procedure in the production of how to adopt new technology, new technology, with high precision, high efficiency and low cost to finish grinding process, is the main task of the grinding. 2. 1 high-speed grinding technology of high-speed grinding to achieve two goals of modern manufacturing technology to improve product quality and labor efficiency. The practice proved: if the grinding speed increased from 35 m/s to 50 ~ 60 m/s, the general production efficiency can be increased by 30% ~ 60%, the durability of the grinding wheel increased about 0. 7 ~ 1 times the workpiece surface roughness parameter value reduced by about 50%. General grinding speed reaches more than 45 m/s is called high speed grinding. Which I have developed in the eighty s ZYS - 811 automatic bearing internal grinder, take the lead in the domestic bearing industry ferrule grinding processing and application of high speed grinding technology, successfully developed a high rigidity, high speed, high power electric spindle and high speed grinding wheel. And high speed grinding is already widely used at home and abroad, and along with the widespread adoption of high grinding ratio, high durability of superhard abrasive such as CBN, the grinding wheel grinding speed reached 80 ~ 120 m/s, is even higher. Mikrosa such as: Germany, Japan KOYO company centerless grinder, Japan TOYO company bearing internal grinder, surface grinding wheel linear velocity of 120 m/s, the inner surface grinding linear speed of 60 m/s ~ 80 m/s. Increase the grinding wheel drive ( Transmission) System of power and improve the rigidity of machine tool is an important measure to realize high speed grinding, and the high speed spindle unit is the most key components of the high-speed grinding machine. In high speed grinding, grinding wheel in addition to should have sufficient strength, also need to make sure that it has good grinding performance, high grinding effect can be attained. In addition, the cooling device is also one of indispensable to realize high speed grinding device. 2. 2 CBN grinding wheel grinding technology of cubic boron nitride abrasive CBN abrasive for short, made by the grinding wheel is called the CBN grinding wheel, the main has the following characteristics: (1) high hardness, high thermal conductivity, good thermal stability, can withstand 1300 ~ 1500 ℃ high temperature. 2 high durability, small abrasion, grinding ratio of up to 4000 ~ 10000 ( Grinding ratio refers to the amount of grinding process to remove the workpiece material and the ratio of the grinding wheel wear) While the common corundum grinding wheel is only 50 ~ 80. (3) small grinding force, grinding heat is small, small machining stress, surface stress thin or not. (4) auxiliary time ( Replacement grinding wheel dressing grinding wheel,) Greatly reduced. To ring for bearing industry in our country, the use of CBN grinding is a kind of new processing technology, the application prospect is very broad, but need to study to solve the following technologies: CBN grinding wheel manufacturing technology, finishing technology, special bearing grinder, grinding coolant and so on. Due to the CBN grinding wheel has a good processing characteristics, the use of CBN grinding wheel bearing ring grinding abroad has already been developed and used in the production, as the production and processing technology of a revolution. Since 1982, CBN grinding wheel in Japan has a large number of applications, and high-speed growth.