The cold extrusion technology of spur gear is a metal plastic forming process with less and no chip, which has the characteristics of high efficiency, high quality and low consumption. The cold extrusion process of spur gear is to put the metal wool into the extrusion die cavity at room temperature, and force the metal to produce plastic deformation in the die cavity under the strong pressure and certain speed of the press, so as to obtain the extrusion parts with required shape, size and certain mechanical properties.
According to the relationship between the metal flow direction and the punch movement direction during the cold extrusion of spur gears, the cold extrusion of spur gears can be divided into the following types:
1.Spur gear forward extrusion
When spur gear is being extruded, the flow direction of metal is the same as that of punch. Under the pressure of the punch, the metal enters the plastic state and flows out of the hole at the bottom of the four dies. Forward extrusion can produce solid parts such as screws and multilayer capacitors, as well as hollow parts such as cartridge cases, riveted tubes and collets.
2.Back extrusion of spur gear
The direction of metal flow is opposite to that of punch in the back extrusion of spur gear. Under the pressure of the punch, the metal flows upward along the gap between the punch and the die, so as to make the parts with the required shape and size. Back extrusion is mostly used to form hollow cup-shaped parts, such as electric blasting nozzle, bearing cover, universal joint bearing, valve ejector rod, shuttle core parts of sewing machine, etc.
3.Compound extrusion of spur gear
During the compound extrusion of spur gears, the flow direction of some metals is the same as that of the punch, while the flow direction of other metals is opposite to that of the punch. Such as spark plug shell, sewing machine shuttle bed, bearing ring, driving gear, etc., can be obtained through composite extrusion process.
4.Radial extrusion of spur gear
During radial extrusion of spur gear, the flow direction of metal is perpendicular to the axis direction of punch. Radial extrusion technology can be used to manufacture cross shaft parts, the tooth profile of spline shaft and the tooth profile of spur and helical small module gears.
5.Upsetting extrusion of spur gear
Upsetting extrusion of spur gear is a process method produced by the combination of cold upsetting and cold extrusion. It has the characteristics of cold extrusion and cold extrusion. During forming, part of the metal flows along the axial direction and the other part flows along the radial direction. Upsetting extrusion process can be used to process some parts with complex shape and structure, such as cover, bicycle flower plate, front tire nut, steel pipe joint and so on.