Pinion-and-rack type turning unit

The invention discloses a pinion-and-rack type turning unit which comprises a turning unit base. The pinion-and-rack type turning unit is characterized in that a driving shaft and a driven shaft are respectively arranged at the left end and the right end of the unit base, turning fixture fixing plates are arranged correspondingly to the output end of each of the driving shaft and the driven shaft, a gear is arranged at the input end of the driving shaft, a rack in transmission fitting with the gear is arranged at the unit base, and the rack reciprocates through a first stroke cylinder fixed on the unit base. The pneumatic straight-push type mechanical structure is environmental friendly, pollution-free, simple in structure and easy to operate and maintain, and turning precision can be guaranteed.