The layout of the machine tool main drive system can be divided into centralized drive system and separation of the transmission system. Centralized transmission layout is all the main transmission system of variable speed drive layout structure and main shaft component concentration in the same box body, Centralized transmission layout of the machine structure is compact, easy to realize the centralized control, with only a box, but the vibration and thermal deformation in the operation structure of transmission. Separate transmission layout is transmission parts and spindle assemblies were installed in two box body, in the middle of a belt or chain drive.

  CNC modular machine tool main transmission system regardless of the kind of layout method, consists of the following components:

1, speed change mechanism

  Variable speed way divided into step speeds change and stepless speed change. Stepless speed changing are institution has the following several kinds: exchange of various institutions this variable speed gear speed change is simple, compact structure, and is mainly used for mass production of automatic or semi-automatic machine, special machine tools and combination machine tools, etc.; Slip gear change mechanism this shift gear is widely used in general machine tool and part special machine tools; Clutch variable motion applied more in the clutch gear mechanisms have tooth clutch, gear clutch friction plate and the clutch.

2, the main drive of opening stop, braking device

  Open stop device is used to control the start and stop of spindle, open stop way has a direct drive, power motivation, and clutch, stop two kinds. When motor power is small, can be directly open power motivation. When motor power is larger, can use the clutch of spindle start and stop. Braking device in unloading workpieces, the size of the processed surface measurement, change the cutting tool and machine tool adjustment, often hope machine tools main motion performs a stop moving as soon as possible. So the main drive system must be installed in the brake device, general can adopt reverse connect brake motor, the brake belt brake, brake shoe brake.

3, arrangement and arrangement of gears

  Variable speed group of sliding gears in general layout on the main shaft, in order to avoid the same sliding gear set of two pairs of gears meshing at the same time, two fixed gear total width should be greater than the spacing sliding gear, which have a certain gap, if no special circumstances, should try to reduce gear axial alignment size. Slip gear axial position permutation usually have narrow and wide type two kinds, in order to reduce the size of the gearbox, both need to shorten the axial dimension, and to shorten the radial dimensions and between them are often interconnected, should consider global according to specific circumstances, so as to properly solve the problem of gear arrangement; Under the condition of strength to allow, as far as possible choose smaller teeth and gear and make slow down transmission ratio is more than a quarter. In this way, both to reduce the gap between the shaft of the variable speed group, and does not interfere with other variable group of the distance between the axis.