Electrically-driven three-stage planetary speed reduction driver

The invention discloses an electrically-driven three-stage planetary speed reduction driver which comprises a driving motor, a planetary speed reduction mechanism, a power output shaft and a motor output flange, and a first-stage sun gear is installed on the power shaft of the driving motor; the first-stage sun gear is connected with the planetary speed reducing mechanism; the planetary speed reduction mechanism comprises a first-stage planetary speed reduction unit, a second-stage planetary speed reduction unit and a third-stage planetary speed reduction unit and further comprises an angle detection device used for detecting the rotation angle of the power output shaft. On the basis that original speed reduction and power output are guaranteed, the three stages of speed reduction units can be independently assembled, then the driver is integrally assembled, the assembling efficiency is improved, each stage of planetary speed reduction unit can be independently replaced and debugged, and the qualified rate of products is greatly increased; each stage of speed reduction unit adopts an independent assembly structure, and the positions of all parts are kept relatively stable, so that abnormal sound caused by assembly error accumulation in the prior art is avoided, and internal resistance generated by axial movement of each stage of speed reduction unit is reduced.