Assembly device

An assembly device is provided, which uses at least three expansion heads that can be separated and approached to each other to form a positioning platform to clamp a sealing ring when they are assembled and can stretch the sealing ring when they are separated from each other. At the same time, using at least three adapters that are staggered from the expansion head, the sealing ring in the stretched state is sleeved on it, and after the adapter is abutted on a component to be assembled, the sealing ring is further pushed into through a separation portion to the component to be assembled. Thus, on the one hand, the stretching range of the sealing ring before being inserted into the component to be assembled is guaranteed, to avoid excessive stretching and damage to the elasticity of the sealing ring; on the other hand, through the assembly device, the sealing ring can be automatically completed from stretching to pushing into the component to be assembled, which saves the operating strength of the operator; a