Gear shaft processing using ordinary lathes, milling machines, etc., rely on the technician for manual operation, low productivity, long time-consuming, low precision. Ordinary lathe is a horizontal lathe which can process many kinds of workpiece parts such as shaft, plate and ring. It is often used in the inside and outside of the workpiece, the end face and various internal and external threads, adopt the corresponding tool and accessories, Drilling, reaming, tapping and knurling. Ordinary lathes are the most widely used lathe, accounting for about 65% of the total number of lathe, because the spindle to the horizontal way so called horizontal lathe.
Usually the gear shaft should be considered to withstand high temperature, wear resistance, fatigue resistance and sufficient mechanical strength, but also take into account both ends of the gear shaft journal and sliding bearings can not use a common grease to lubricate. Because the usual grease can contaminate the melt, it can only be lubricated using its own melt. For the design of the mechanical strength of the gear shaft can refer to the "mechanical design manual" in the shaft parts design requirements, will not repeat them here.
Now for the gear shaft in the design of a few special issues for a discussion. Select the smaller axial force of the gear form of the core of the melt pump components for the gear components, gear rotation and meshing on the one hand can squeeze the melt between the teeth, so that the material from one end to the other end of the other side of the gear The engagement can close the low pressure chamber and help to increase the output pressure. Spur gears and helical gears are easier to manufacture, but the self-cleaning of the spur gears is poor and the pressure fluctuates at higher speeds. While the helical gears overcome the problem of poor self-cleaning and pressure fluctuations, the Changzhou vacuum pump can not To avoid a greater axial force, which exacerbates the gear shaft and sliding bearing wear, oil-free screw vacuum pump will lead to tooth side gap melt serious shear, affecting the quality of the final plastic products. In order to balance the axial force in the heavy load conditions, smooth operation, the best structure of the gear is a herringbone gear.
At present, the processing of a chevron gear assembly is usually the practice of processing two helical gears and a gear shaft, after the use of gear wheel and gear shaft with the static balance of the two helical gears heated to the same time after the installation to Gear journal of the specific location, the use of gear Yi's heat shrinkage into a chevron gear components. In addition to the load required to meet the material delivered by the melt pump, it should also be considered that the pump is continuously operated at high temperatures. The ideal material is a forged and heat-treated forged steel. In order to improve the wear and fatigue resistance of the gear shaft, Its reliability, after machining should also be softened by salt bath surface treatment. The internal stress of the gear shaft Select the appropriate gear journal and the combination of the two helical gears called the chevron gear wheel between the static fit between the interference plate is to reduce the load in the journal journal key. By the experience that, if the interference is not enough, the pump will run at the gear shaft and herringbone gear accuracy, you can save processing costs. The friction between the ends of the gear shaft at both ends of the gear shaft is caused by the relative operation of the gears at both ends of the gear shaft. If the gear shaft at both ends of the journal and the sliding bearing with the tight, it will cause poor gear shaft lubrication, resulting in excessive friction, resulting in reduced clearance and clearance of the broken gear shaft force is too large and broken , If the two with the loose, the life of the sliding bearing is also very short, the damage to the bearing will increase the friction of the gear shaft.