Gears processed by gear grinding have the advantages of low transmission noise, high transmission efficiency and long service life. Gear grinding was once considered as an expensive gear processing method used in aviation or other high-tech fields. But now, the concept has changed: the efficiency of gear grinding machine has been improved, the performance of grinding wheel has been better, and the high cost has been greatly reduced. Therefore, gear grinding has been applied to gear processing on a large scale, such as the manufacturing of automobile and motorcycle gears, and has reached the level of universal application. In fact, all the first-class automobile gear suppliers have generally owned gear grinding machines in order to maintain their competitiveness. In the next 2~5 years, automobile industry will gradually become a big growth market for hard tooth surface processing max. Because grinding can remove heat treatment distortion, many gearboxes use grinding gears to better control transmission lost motion and noise. The gear grinding process has basically matured and is growing rapidly in the whole gear industry.
Progress of gear grinding machine.
The efficiency of today's gear grinding machine is much higher than that of the same type of machine tools ten years ago. This stems from a series of major improvements:
1 airborne measurement.
Many gear grinding machines become more accurate because they are equipped with airborne measuring systems. Because the on-machine measurement is used, it is not necessary to remove the gear from the workbench and send it to other places for testing, thus avoiding the secondary installation error during reprocessing. During machining, the airborne measuring system firstly analyzes the gear, then compares the measured parameters with the theoretical design parameters, and obtains the required correction amount. After collecting these correction data, the control system automatically adjusts the gear grinding processing state, and then carries out gear grinding and measurement. Repeat this cycle until the required accuracy is achieved. The integrated airborne measurement and correction system makes the modern gear grinding machine more efficient.
At home, for example, YK75100 forming grinding wheel gear grinding machine of qinchuan development co., ltd. and CEP 1000 overhead gear measuring system of Chengdu tool research institute have successfully tried open-loop on-machine measurement (feedback and control of measured data need to be done manually). However, as far as the domestic level is concerned, the precision of machining and measurement needs to be further improved.
2 direct driver
In recent years, the use of compact direct driver in grinding wheel spindle and gear workpiece spindle is increasing day by day. Direct drive spindle can avoid transmission chain error. Therefore, the application of direct driver in the cycle of "grinding wheel-grinding gear", with better grinding wheel and multi-axis linkage control, can eliminate the high-frequency error of cutting lines, distorted geometry, gear use noise and harmful vibration.
3 Automation
The word "automation" is increasingly used in gear grinding, especially in flow production, including workpiece installation, tool change and inventory classification synchronized with workpiece flow. Automation eliminates idle time of machines and helps to reduce waiting time between processes. nextpage
4 gear grinding machine software.
Windows-based software is also widely used in today's gear grinding machines like personal computers (such as Windows-based design systems and numerical control systems). In the past, it was only possible to draw on paper. Now, the design plus correction software package combined with graphical interface and algorithm software can make gear geometry design programmed and local manufacturing simulated.
The high-precision closed-loop control among drive, ball screw and position sensor is realized by the application of software. Many components of the new generation gear grinding machine are equipped with position sensors separated from the driving unit, so they have higher accuracy and thermal stability. Absolute displacement sensor and absolute coding technology ensure the high-speed transmission of feedback data and the stability of machine tool transmission on the premise of high positioning accuracy.
5 machine tool profile.
Today's gear grinding machines are smaller in shape and occupy less land, which enables manufacturers to make better use of limited production areas to "create" more available space, instead of spending money on "bricks and cement" for expanding factories, they are used to purchase equipment.
6 new material grinding wheel.
Advanced ceramic bonded grinding wheels and electroplated cubic boron nitride (CBN) grinding wheels have the same high production efficiency. Due to the use of new materials in the "mixed particle" composite and the improvement of bonding process, the strength and toughness, shape accuracy retention, material cutting force and durability of the ceramic bonded grinding wheel have been improved. These excellent properties are derived from high-performance particle structure and increased porosity. At the same time, good grain structure reduces grinding pressure and grinding temperature.
At present, it is difficult to select electroplated CBN grinding wheels and ceramic bonded grinding wheels due to the use of new cold grinding ceramic abrasive grains in high-pressure coolant system. However, compared with ceramic bonded grinding wheels, electroplated CBN grinding wheels have simpler operation, shorter installation time and lower requirements for operators' technical ability, which provides a more feasible low-cost choice than CBN abrasive ceramic bonded grinding wheels.
Reishauer Company of the United States has tested these ceramic grinding wheels with their "cold grinding" process, and the conclusions are as follows: ①max's new alumina abrasive and ceramic abrasive grinding wheels can produce the same or less pressure than CBN abrasive ceramic bonded grinding wheels. ② Contrary to expectations, ceramic grinding wheels are more efficient and durable than CBN grinding wheels. ③ Unlike electroplated CBN grinding wheels, ceramic grinding wheels can be sharpened on gear grinding machines, while electroplated CBN grinding wheels must be sent back to the original factory for grinding.
Ceramic grinding wheels have high cutting speed (such as 60m/s), so they are suitable for mass production of gears. This kind of grinding wheel has a longer service life than other previous grinding wheels (such as alumina grinding wheels). The new grinding wheel technology is more used in grinding worm grinding wheels for gears of 200mm and below with large output max.
7. Reduction of grinding cost.
Nowadays, the cost of gear grinding has been greatly reduced, for many reasons, such as high cost-effective models based on modular design, numerical control systems, process production, etc. Even gear grinding machines integrating all the above-mentioned advanced technologies are much cheaper than previous models. Mass production has shortened the single-piece production cycle by 50%~70%, and the cost of worn products (grinding wheels and diamond modifiers, etc.) has also been greatly reduced.
