| 摘要 |
A CNC lathe provided with two opposed head stocks (2a, 2b), two turret type tool rests (3a, 3b), and a slanting base (1), the first head stock (2a) being fixed to the base (1), the second head stock (2b) being provided so that it can be moved and positioned in the direction of a main shaft only, two tool rests (3a, 3b) being arranged at the back of the head stocks (2a, 2b). A CNC lathe having the above-mentioned construction, in which each head stock is provided independently with a main shaft motor (21), a mechanically engageable and disengageable main shaft indexing driving unit (23), and main shaft side and indexing driving unit side encoders (27, 26), adapted to carry out a phase matching operation by rotating an indexing motor (40) on the basis of a phase difference detected by the encoders when the main shaft indexing driving unit (23) is connected to a main shaft (11) and when transfer of a work (16) is made between the main shafts (2a, 2b). A CNC lathe having the above-mentioned construction and provided with a synchronizing control unit (53) adapted to segment the output pulses from the encoders (27) on the main shafts on a minute time basis and correct a speed command in accordance with the magnitude thereof. According to the present invention, a CNC lathe having a first head stock of a high rigidity, capable of using a bar feeder of a conventional construction and having an improved efficiency in carrying out a work machining operation including an indexing machining operation using two main shafts an improved efficiency of machining a bar material which requires a cutting-off when the transfer of the work is made between the main shafts can be obtained. |
