The invention discloses a water
injection device for water-assisted injection molding, and the water
injection device is simple in structure and reliable in action. The water
injection device comprises a plug 1, a valve body 2, a seal pad 3, a
diameter-variable high-pressure
water pipe joint 4, a position-adjustable
flange 5, a valve core 6, an SDA thin air cylinder 7, an adjusting nut 8, an air cylinder joint 9, a shaft coupler 10, a shaft
coupling pin 11, an air cylinder mounting bracket 12, an O-shaped seal ring 13, a rectangular seal ring 14, a valve body mounting bolt 15, bracket mounting pads 16 and bracket mounting bolts 17. The end surface of the valve core is designed to be conical, so that the phenomena of difficulty for water injection and high-pressure water advancing direction deviation caused by solidification of molten plastics near a water injection hole can be removed and reliable water injection and accurate water injection direction are guaranteed; the conical surfaces of the valve core and the valve body are clung to each other, and various auxiliary seal rings are arranged on the valve core, so that a
needle valve is guaranteed to excellently seal up
sizing materials and water; an air cylinder is adopted to drive a valve needle to be started / stopped, and the action is reliable; the water injection device is suitable for water-assisted injection molding and similar processes.