A motor system including: a cylindrical body; a converter configured to convert a two-directional rotation into a one-directional rotation; a rotatable shaft configured to be (a) disposed inside of the cylindrical body, (b) rotatable in both a counterclockwise direction and a clockwise direction, and (c) coupled to a drill bit through the converter; a driving piston configured to be coupled to the rotatable shaft and configured to divide the cylindrical body into a first chamber and a second chamber; and a flow piston configured to change flow direction of the fluid within the cylindrical body to drive the driving piston, wherein the driving piston is configured to be driven by the fluid via a pressure difference to move in a forward direction and in a reverse direction.

A mechanism 21 for converting rotating motion to rotating and reciprocating motion and/or vice versa. The mechanism has a housing or support 22, a first member 23 rotatable about a first axis and reciprocable along the first axis, and a second member 2 rotatable about a second axis spaced from the first axis. Rotation of the first member 23 or the second member 25 causes rotation of the other member. A guide 29a, 29b is configured to contact a cam surface 27a, 27b. The cam surface or the guide is provided on the first member 23. The cam and guide are configured to cause the first member 23 to rotate upon movement of the first member along the first axis, or to move along the first axis upon rotation of the first member 23.

A mechanism 21 for converting rotating motion to rotating and reciprocating motion and/or vice versa. The mechanism has a housing or support 22, a first member 23 rotatable about a first axis and reciprocable along the first axis, and a second member 2 rotatable about a second axis spaced from the first axis. Rotation of the first member 23 or the second member 25 causes rotation of the other member. A guide 29a, 29b is configured to contact a cam surface 27a, 27b. The cam surface or the guide is provided on the first member 23. The cam and guide are configured to cause the first member 23 to rotate upon movement of the first member along the first axis, or to move along the first axis upon rotation of the first member 23.