The mounting assembly comprises a base member; a bracket with a portion protruding from the base member; a mounting bending part attached to the protruding portion and including at least one elastic pre-fixing leg, and at least one fixing bending leg; and a tightening member for tightening the mounting bending part to the bracket. The mounting bending part and the protruding portion can be arranged to clamp to each other in a first relative position where the fixing bending leg is between the base member and the protruding portion; and in a second relative position where the pre-fixing elastic leg is between the base member and the protruding portion, and the fixing bending leg is out of a position between the first relative position.