Method for forming helical gear by radial cold extrusion and die thereof

Abstract

The invention discloses a method for forming a helical gear by radial cold extrusion and a die thereof. The die comprises an upper die and a lower die and adopts a double male die structure consisting of an upper male die (14) and a lower male die (16), wherein a floating mechanism is arranged between a fixing plate and a lower die holder and comprises a combination female die (8), a supporting plate (5) and a spring (17) arranged between the combination female die and the supporting plate; the combination female die and the fixing plate are supported together through a bearing; the supporting plate and the lower die holder are supported together through a bearing; in a cold extrusion forming process, the upper male die and the lower male die act on a blank together so that the blank is formed by radially and plastically flowing in the cavity of the combination female die; when the upper male die is engaged with the combination female die, a circumferential force is applied to the combination female die and the combination female die rotates through a thrust bearing, so the moving coordination of the male and female dies is ensured effectively; and when the upper male die and the lower male die co-act and extrude the blank, the spring of the floating mechanism is compressed along with an extruding process under the action of frictional force and the combination female die floats up and down so that the forming load during the extrusion forming of the helical gear is reduced.

Description

technical field [0001] The invention relates to a gear cold extrusion forming technology, in particular to a helical gear radial cold extrusion forming method and a mold for realizing the method. Background technique [0002] As one of the most important parts of mechanical transmission, helical gears are widely used in machinery, automobiles, electrical appliances and other industries. It has the characteristics of stable transmission, accuracy and reliability, and high transmission efficiency; It takes a lot of time, low efficiency, and a lot of material waste, and the mechanical properties of the processed helical gear are low, which is mainly reflected in the fact that the metal fiber structure is cut and discontinuous. [0003] The cold extrusion forming process can make up for the lack of mechanical processing. At present, the axial extrusion forming method is mainly used for the cold extrusion forming of gears, and it is mainly used in the processing and forming of sp...

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Problems solved by technology

[0002] As one of the most important parts of mechanical transmission, helical gears are widely used in machinery, automobiles, electrical appliances and other industries. It has the characteristics of stable transmission, accuracy and reliability, and high transmission efficiency; It takes a lot of time, low efficiency, and a lot of material waste, and the mechanical properties of the processed helical gear are low, which is mainly reflected in the fact that its metal fiber structure is cut off and discontinuous

[0003] The cold extrusion forming process can make up for the lack of mechanical processing. At present, the axial extrusion forming method is mainly used for the cold extrusion forming of gears, and it is mainly used in the processing and forming of spur gears; when the gears are axially extruded, multiple passes are required. Extrusion, or the gradual and continuous extrusion of the gear blank from the transition shape to the final shape inside the mold, but there is still a phenomenon that the filling of the tooth shape is not full

And because the helical gear has a certain helix angle, it is more difficult to cold-extrude the helical gear, such as large forming load and difficulty in ejecting the formed part.

[0004] Chinese patent ZL00266599.9 discloses a cold-temperature extrusion molding die for internal and external circular helical gears, the die of the lower die is set on the lower die base through support blocks and bearings, that is, the die is fixedly supported; in this way, the gear is extruded , the position of the die does not change, the forming load is transmitted to the bearing, and the forming load is large; and the friction force does negative work during the forming process; axial extrusion is used in the extrusion molding, and the forming process is a gradual extrusion process, and the material In the extrusion process, the mechanical state is not strictly three-dimensional compressive stress, which leads to poor compactness of the formed parts

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