Automatic assembling device and method for horizontal bar shock absorber

An automatic assembling device for a horizontal bar shock absorber comprises an inflation oil injection cylinder and a connecting base, a vacuum valve, an oil injection valve and an inflation valve are sequentially installed on the upper portion of the cylinder face of the inflation oil injection cylinder from left to right, and the vacuum valve and the oil injection valve are attached together in position; and a limiting mechanism A and a limiting mechanism B are sequentially installed on the lower portion of the cylinder face of the inflation oil injection cylinder from left to right, the limiting mechanism A is correspondingly located below the vacuum valve, and the limiting mechanism B is correspondingly located below the oil injection valve. The right end face of the inflation oil injection cylinder is connected with the connecting base, the right side of the connecting base is connected with a mounting base, and the mounting base is fixed to a mounting platform. A cylinder pushing device is correspondin