Processing of gear box body is a delicate craft, material, structure and processing procedures, skills need to be carried out in accordance with the requirements strictly, we want to gear box body of the high technique requires are put forward and accuracy requirements, improve the quality of the gear box and the use of performance. The research on machining technology of high precision gear box is introduced.
1. Numerical control machining technology of box type parts.
1.1 structure and characteristics of parts.
Of gear box of the various components are relatively complex and enclosure wall thick is not balanced, in need of stiffened plate fastening, need to carry on the processing of parts, including the box body top and bottom plane, bearing hole, oil, end thread and check processing and so on. In order to ensure the final assembly precision of the box, the precision and roughness of these parts need to be precisely guaranteed.
1.2 parts materials
Used for casting body material needs to have lower cost, with wear-resistant, plasticity and damping properties, ordinary gear box body is relatively more choose HT in between 200 and 400 of the gray cast iron. Advanced some also use ball mill with cast iron but under special circumstances, if have strict requirements on accuracy, you can choose to wear resistant cast iron or can choose steel welded structure, after high temperature annealing to remove internal stress of the structure, and ensure the stability of the box body.
1.3 main technical requirements of parts.
The nc high-precision machining of gearbox housing must be operated strictly according to relevant technical requirements. Once the technical parameters are not up to standard, the machining gear box is not qualified, and there are many places to pay attention to when processing.
Compared to ordinary low-speed gear box, the size of the hole, the size of the geometry and the surface roughness. In general, the parallel shaft hole accuracy of the gearbox box body reaches the T6 level, and the roughness of the surface roughness of the parallel shaft hole needs to be controlled within ra0.8-1.6 um. For the size of the geometric shape precision, it only needs to be controlled within the tolerance range of the hole.
For the size and position of the parallel axis holes. At the time of processing, the distance between the supporting holes of the gearbox and the position relation are also considered. In general, the distance between the center distance must be between 0.02 and 0.08mm, and the parallelism of the axis line is within 0.03-0.1mm.
1.4 processing technology
Gear box datum and points up and down surface, if the gear box body is relatively small, so usually can be conducted on shaping machine and ordinary milling machine processing, whereas may need to be done on the gantry planer, gantry milling machine processing; For the casing diameter is less than 50 mm hole, generally can be used to drill a expansion of a hinge, if the hole is more than 50 mm, you can use rough boring half fine boring boring scheme for a fine processing, after the fine boring, need to use floating boring blade reprocessing, at this moment is generally adopts the honing, rolling process method, etc.
In the process of machining the gearbox, we should pay attention to the machining precision of the box, only the high precision can ensure the final assembly precision. But the guarantee of high precision need process, especially for oxygen, such as blast furnace using high speed gear box, the requirement of accuracy grade is higher, in this article, the author, after many years of technical experience, to studying of related problems, on the basis of advanced numerical control processing equipment, to adjust the precision of the equipment, and use all kinds of processing methods, processing of gear box body. This paper explores a set of process technical scheme which is suitable for high precision gear box.