The existing main shafts used for horizontal machining centers are mainly in two forms: electric main shaft and gear main shaft.
The electric main shaft can realize high speed, and the gear main shaft can realize high power and large torque.
The existing gear spindle with a torque of 2 000 N * ni or more has a speed of 4 500 i/miti or less, which often limits the scope of use of machining centers as general-purpose processing equipment, and also limits the improvement of production efficiency. The reason is that high torque (2 000 N•m or more) gear spindles generally adopt gear transmission schemes with large reduction ratios.
The bearings supporting the main shaft of the large horizontal machining center are lubricated with oil and gas, which increases the speed of the main shaft, so that the gear main shaft structure used in the horizontal machining center has the dual advantages of large torque and high speed. In the case of adopting a two-stage gear transmission structure, the spindle speed range is realized: 35-6000r/min, and the spindle torque can reach 2045N*M, which reduces the outline size and quality of the spindle. It is the gear spindle structure of the horizontal machining center. improvement of.
The large size and high quality of the main shaft make the feed speed of the machine tool lower; in addition, the gear spindle bearing uses grease lubrication, which greatly limits the rotation speed of the main shaft (for example, the spindle bearing diameter is 110 mm and the grease lubrication spindle speed is 4 500 r / min or less). Therefore, the existing gear spindle has low working efficiency and limited use range.
