我厂过去在六角车床上加工汽车转向纵拉杆,夹具采用手动三爪卡盘。对于加工这种圆筒形薄壁工件来说,夹紧力稍小就夹不紧,夹紧力太大了又造成工件变形严重。夹紧力完全取决于操作工人的体力状况和经验,很不稳定。 一九七四年,我厂投产了一台加工汽车转向纵拉杆的鼓轮式组合机床(见本刊1977年第3期),我们使用载荷继电器来控制自动送进机械扳手的输出扭矩,从而精确地控制了螺旋夹紧虎钳的夹紧力。 我厂建厂以来一直采用电流继电器来控制支架式机械扳手的输出扭矩,即使是在对夹紧力要求并不严格的场合,也经常出现夹不紧,或者因夹紧力过大而损坏夹具的现象。而按照机械扳手的额定输出扭矩来计算或使用,按理不应当产生上述现象。长期的生产实践说明用 I plant in the past on the hexagonal lathe machining vertical shift lever, the fixture using a manual three-jaw chuck. For the processing of such cylindrical thin-walled workpiece, the clamping force is slightly smaller on the folder is not tight, clamping force is too large and cause serious deformation of the workpiece. Clamping force completely depends on the physical condition and experience of the operating workers, very unstable. In 1974, our factory put into production a drum-type combined machine tool (see Issue 3, 1977) that used to process car steering trailing sticks. We used a load relay to control the output torque of the automatic mechanical wrench Precise control of the clamping force of the spiral clamping vise. I plant has been built since the current relay to control the output torque of the mechanical wrench rack, even in the clamping force is not strictly required occasions, often appear tight clamp, or due to clamping force is too large and damage the fixture The phenomenon. In accordance with the mechanical wrench rated output torque to calculate or use, should not be reasonably the above phenomenon. Long-term production practice instructions