Semi-closed oil pumping unit

A semi-closed oil pumping unit comprises a support. A walking beam is hinged to the support, a horse head is installed at one end of the walking beam, the other end of the walking beam is hinged to the upper end of a connecting rod, the lower end of the connecting rod is hinged to a crank, and the crank is connected with a motor. A front side baffle wall is arranged at the edge of the support, a rear side baffle wall is arranged on the side of the motor, and sliding rails are arranged at the two ends of the rear side baffle wall and the two ends of the front side baffle wall in a connected mode. A fixed column is arranged on the side of the rear side baffle wall and located at one end of the corresponding sliding rail, a sliding trolley is arranged on the sliding rails in a matched mode, and multiple movable columns are arranged between the sliding trolley and the fixed column. A first connecting rod and a second connecting rod are hinged to the middle of each movable column, the ends of each first connecting rod are hinged to the ends of the second connecting rod on the adjacent movable column, and every two first connecting rod and second connecting rod sets form a parallelogram structure. The middle of the fixed column is hinged to the first connecting rod and the second connecting rod on the closest movable column. The middle of the sliding trolley is hinged to the first connecting rod and the second connecting rod on the closest movable column.