Simple guide rail, guide rail assembly and machine tool outer cover

The utility model discloses a simple guide rail, a guide rail assembly and a machine tool outer cover. The simple guide rail comprises a mounting plate part, a first bent plate part and a second bent plate part. The mounting plate part is vertically arranged; the first bent plate part is obliquely arranged relative to the horizontal plane, and the right side of the first bent plate part is connected with the upper side of the mounting plate part; the second bending plate part is obliquely arranged relative to the horizontal plane, the right side of the second bending plate part is connected with the left side of the first bending plate part, the left side of the second bending plate part is a free side, and the second bending plate part is opposite to the first bending plate part left and right; the simple guide rail is an integrated sheet metal part, and the upper side of the first bent plate part and the upper side of the second bent plate part form a bearing part used for bearing a sliding block or a rolli