Heat treatment method and special tooling for lawn mower sprocket

Abstract

The invention discloses a method for heat treatment of lawnmower sprockets and special tooling, which performs batch heat treatment of sprockets through the special tooling, and the special tooling includes a mounting chassis and a mounting seat arrayed on the mounting chassis, the mounting seat There is a positioning rod on the outer edge, and a flow hole is provided in the middle of the mounting seat. The sprocket is stacked on the mounting seat. The outer tooth groove of the sprocket corresponds to the position of the positioning rod of the mounting seat. The inner hole corresponds to the position of the flow hole of the mounting seat, and the charging step, preheating step, heating step, quenching step, and tempering step are carried out in sequence during the heat treatment process, and each is set according to the charging method of the special tooling. The temperature parameters and time parameters of the steps are used to achieve a better heat treatment effect, which not only improves the production efficiency through batch processing, but also can control the deformation of the heat treatment and improve the hardness accuracy of the sprocket.

Description

technical field [0001] The invention relates to the technical field of heat treatment, in particular to a method for heat treatment of a lawnmower sprocket and special tooling for heat treatment of the method. Background technique [0002] The sprocket is a common part in the gearbox. In the gearbox of the lawnmower, the national standard (GB14212) stipulates that the axial runout of the sprocket should not be greater than 0.3mm. In the heat treatment production, the deformation of the sprocket needs to be controlled. and hardness. [0003] In the traditional sprocket tooth heat treatment process, the induction heat treatment of the sprocket tooth (45 carbon steel) is to use the rotating sprocket as a whole to immerse in quenching oil, that is, after the sprocket is heated to the quenching temperature by induction, it is directly immersed in quenching oil in the rotating state Medium cooling and quenching, tempering after taking it out, but the use of this process usually l...

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Problems solved by technology

[0003] In the traditional sprocket tooth heat treatment process, the induction heat treatment of the sprocket tooth (45 carbon steel) is to use the rotating sprocket as a whole to immerse in quenching oil, that is, after the sprocket is heated to the quenching temperature by induction, it is directly immersed in quenching oil in the rotating state Medium cooling and quenching, tempering after taking it out, but the use of this process usually leads to cracks or fractures in the teeth of the sprocket, and the hardness of the surface is uneven, that is, the hardness of the same part (such as the top of the tooth and the bottom of the tooth) is different More, at least up to HRC (Rockwell hardness) 10 degrees or more, in addition, deformation after heat treatment will inevitably occur, especially the twisted wave deformation is difficult to be flat

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