Structural characteristics of precision forging die for planetary gear

The pre forging die and final forging die need to be designed for forming planetary gear by “one heat two forging”. The parting surfaces of the two sets of dies are the same, both of which are composite parting surfaces composed of the back cone parting surface at the big end of the gear and the horizontal parting surface at the top. Because the working condition of the die is very bad, the combination die structure is used to improve the die life.

The diagram shows the structure diagram of the planetary gear pre forging die. The tooth die of the pre forging die is in the upper die, the contact time between the tooth die and the high-temperature billet is short, and the temperature rise of the die is small, which is conducive to improving the life of the tooth die. In addition, the oxide is not easy to accumulate in the cavity of the tooth model, so as to ensure that the forging is separated from the tooth die instantly after the forging. When the elastic ejector is installed on the upper die for pre forging, the deformation of the billet is large, In order to ensure the accuracy of the upper and lower die guide, the guide pillar and guide sleeve are used to guide the die. The upper base plate and the lower base plate are respectively fixed on the upper template and the lower template with screws. In order to make the figure clear, the screws connecting the upper and lower base plates and the upper and lower templates are not shown in Figure 1.

The tooth mold and the tooth mold sleeve are prestressed, and the screw uses the upper pressing ring to fix the tooth mold sleeve on the upper template. The back cone formwork and the back cone formwork sleeve are prestressed, and the screw is fixed on the lower formwork by the lower pressing ring. At the beginning of forging, the upper punch is at the lower limit position under the action of spring. The upper die goes down. The guide post is first led into the guide sleeve, then the upper punch contacts with the blank. The spring is compressed, and the blank begins to forge. After forging, the upper die goes up, and the forging deformation force is eliminated. The tension of spring makes the forging detached from the tooth die.

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