The function of the stop washer and the spring washer is to prevent the screws from loosening. They are different in structure. The spring washer is equivalent to a spring with a number of turns. When the screw is pressed, the spring force of the spring pad increases the friction of the screw to prevent loosening. The retaining washer has a raised fixing leg on the inner ring, and there are 3~4 protruding locking legs on the outer ring. Generally, a keyway is required on the machine shaft on which the retaining washer is mounted, and the retaining washer and the nut are fixed. After locking, pick up the locking foot on the outer ring and press it with one or both of the six faces of the nut to prevent the nut from loosening. The retaining washer is more suitable for severe vibration.