Integral forging near net shaping process for triple gear block, and prepared gear shaft

Abstract

The invention discloses an integral forging near net shaping process for a triple gear block. The process is characterized by comprising the following steps of: blanking and preparing blank; extruding a handle part in a forward direction; pre-upsetting; extruding to obtain a small gear; performing spheroidizing; performing saponification of phosphorus; and extruding to obtain a large gear. The adopted technological scheme has the advantages that: (1) the triple gear block is subjected to integral forging near net shaping; (2) a bevel gear is pre-set, and a material at a tooth space is extruded out, so that the disadvantage of folding caused by pressing a spoke wheel during rear-pass warm forging is avoided; (3) a large straight gear is obtained through cold extrusion, and positioning orientation is adopted, so that the coaxiality and the position of a bevel gear mold and a large straight mold are guaranteed; and by using a lower pressure block, a spoke plate is prevented from being deformed due to gear extrusion, the disadvantages of gear root bending, gear face galling, and damage to a gear mold are eliminated, and in the tooth profile, the undercutting caused by hobbing is avoided.

Description

technical field [0001] The invention belongs to the field of near-net forming of metal materials, and in particular relates to the near-net forming of integral forging of triple gear shaft products. Background technique [0002] The triple gear shaft is a key low-speed and heavy-duty part in the transmission system, and it is mainly used for the load-bearing feet of heavy-duty trucks. At present, there are two methods for processing the triple gear shaft: one is the integral casting method; the other is the combination of welding or key and pin connection after split processing. [0003] The triple gear shaft products produced by integral casting method, the current general material is ZG270-500 (ZG35), its tensile strength σb (MPa) ≥500, yield strength σs (MPa) ≥270, elongation δ5 (%) ≥ %18, reduction of area ψ (%) ≥%25. Product defects are: there are internal pores, segregation, and inclusions; the strength cannot be guaranteed, and fracture accidents often occur during ...

AI Technical Summary

Problems solved by technology

Product defects are: there are internal pores, segregation, and inclusions; the strength cannot be guaranteed, and fracture accidents often occur during use; the hardness of the tooth surface is low, and the wear is fast, which affects the transmission accuracy

Process defects are: 1. Forged rounded corners are generally larger than 1 / 4 of the average wall thickness, too small will lead to cracking due to stress concentration at the rounded corners

2. It is easy to cause pores, segregation, and inclusions inside the product; 3. During the processing, the rod is prone to severe bending, which makes it impossible to assemble and the yield is low; 4. The casting method is used for production, resulting in low product strength and poor hardness. Meet the performance requirements of triple gear shaft products; 5. Serious environmental pollution

[0004] The main defects of the method of separate processing first, and then using key and pin connection to produce triple gear shaft products are: 1. Each part is processed separately, resulting in large material loss; 2. High requirements for the position of the keyway and pin hole, The requirements for machining equipment are high, and the processing cost is also increased accordingly; 3. Opening keyways on shafts and gears will greatly reduce the overall mechanical strength of the parts

4. Since the tooth shape needs to be machined, the efficiency is very low, only 3% of the present invention

[0005] The main defects of triple gear shaft products are produced by welding after split processing. The main defects are: the thermal deformation during welding will cause the beating of the gears to increase during meshing, which will affect the transmission accuracy; the virtual welding and air holes at the welding place will lead to insufficient overall strength.

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