Development trends have emerged in gear-making machine tools and gear-making technology

Update:24-05-2022
Summary:

In order to meet the requirements of the gear processin […]

In order to meet the requirements of the gear processing industry for manufacturing accuracy, production efficiency, clean production, and quality improvement, the following development trends have emerged in gear-making machine tools and gear-making technology.​​
1. Numerical control
After the CNC control of each motion axis of the machine tool and the linkage between some axes, it has the following advantages:
(1) The functions of the machine tool have been increased, such as hobbing with small tapers and drum gears, which has become extremely simple.​​
(2) The transmission chain is shortened, and after semi-closed loop or full closed loop control is adopted, the positioning accuracy and repetitive positioning accuracy of each axis can be improved through numerical control compensation, thereby improving the machining accuracy and C p value of the machine tool, and increasing the reliability of the machine tool. sex.​​
(3) When changing varieties, the time for calculating and changing gears and differential gears, feeding and main shaft shifting is omitted, and the gear shaper also saves the time for changing inclined guide rails, thereby reducing auxiliary processing. Time increases the flexibility of the machine tool.​​
(4) Since the mechanical structure has become simpler, it can be designed to be more conducive to improving the rigidity of the machine tool and minimizing thermal deformation.​​
(5) There is no mechanical connection between the axes, and the structural design becomes typical, which is more conducive to the implementation of modular design and manufacturing.​​
2. High speed and high efficiency
The high speed of gear processing machine tools such as gear hobbing machine, gear shaping machine and gear grinding machine mainly means that the machine tool has high tool spindle speed and high table speed, which are the main indicators to improve cutting efficiency. The speed of the hob spindle of the traditional mechanical hobbing machine is usually up to 500r/min, and the maximum speed of the table is 32r/min. The tooth cutting speed is developed from 100m/min to 500~600m/min, and the cutting feed speed is developed from 3~4mm/r to 20mm/r, which makes the maximum speed of the main shaft of the gear hobbing machine up to 5500r/min, and the highest working table. The rotating speed can reach 800r/min, and the moving speed of machine parts can also be as high as 10m/min; the high-power spindle system enables the machine tool to use grinding wheels with larger diameter and length for grinding, which is beneficial to increase the life of the grinding wheel and also help the operator to choose the most suitable grinding wheel. The optimal grinding parameters are used to complete the grinding process. High-efficiency machining is guaranteed by the use of special technologies in all aspects of the machine: cast bed with optimum vibration absorption; integrated cooling medium circulation system for optimum thermal stability of the machine; large inclination and smooth design of the protective baffles in the cutting area It can quickly and effectively discharge the chips produced by dry cutting; it has a feed system driven by a preloaded, backlash-free ball screw; it has a wear-resistant linear guide or a PLC-controlled quantitatively lubricated cast iron guide, etc. The application of the electric spindle improves the tool spindle, and the increase of the speed of the table is the use of a high-precision helical gear pair or a torque motor. Electric spindle and torque motor have the advantages of high rotation accuracy, no backlash and no maintenance.​​
3. High precision
Due to the use of high-precision, high-rigidity linear guides with preload, ball screws, rolling bearings, electric spindles, torque motors and numerical control technology, the precision of the gear machining machine tool under high-speed machining conditions is guaranteed and improved. The accuracy of the electric spindle is generally 0.002mm in radial runout and 0.001mm in the axial direction; the positioning accuracy of the annular torque servo motor is 0.5″, and the repeatable positioning accuracy is 0.01″; the positioning accuracy of the linear motion axis is less than 0.008mm, and the repeated positioning accuracy is less than 0.005 mm. Although the gear hobbing and gear shaping are rough machining, they can still reach the DIN6~7 level precision under the condition of high-speed cutting, which provides a guarantee for the high precision of the subsequent finishing process. With the improvement of the production efficiency of gear grinding machines, the reduction of the cost of single-piece gear grinding, and the continuous pursuit of higher precision requirements for automotive gears, the market demand for gear grinding machines is increasing; at the same time, with the development of numerical control technology, various The function extension between the machine tools is easier to achieve. Therefore, under the pressure of fierce market competition, the world's major gear machine tool manufacturers have joined the ranks of gear finishing machine tools represented by gear grinding machines. The development of this trend will make the future automotive gear processing more and more adopt the tumble-grinding process.

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