Reciprocating hydraulic machine, especially a motor, and dosing apparatus comprising such a motor

A hydraulic motor, comprising:

• a body closed at its top by a removable cover;
• an exchangeable cylindrical liner located in the body interior and defining a cylindrical housing for the piston, the liner changed quickly by removing the cover and extracting the liner in a translational movement, and fitting a new liner;
• a piston able to slide in a reciprocating movement in the cylindrical housing, a chamber being formed on each side of the piston;
• hydraulic switching means for feeding and evacuating the respective chambers, these switching means being able to adopt two stable positions;
• control means having elastic means for abruptly bringing about changes in the position of the switching means;
• and triggering means able, at the end of the stroke of the piston, to bring about the change in position of the switching means, wherein
• the piston is a simple piston, having a closed cross section;
• and the switching means are arranged in the body of the machine, radially on the outside of the cylindrical housing in which the piston slides.