The present invention relates to an energy transforming unit adapted to convert reciprocating forces (Fl) into rotating axle movements on at least one force transmitting axle and/or into electrical power. The unit comprises at least one restriction device (3, 4, 5) which is directly connected to the force and which is arranged to forward the incoming reciprocating forces (Fl) into a movement over at least one conversion module (2a-d, 56, 64, 73, 80, 81, 87, Cm). The energy transforming unit is characterized in that the at least one restriction device (3, 4, 5) is delimiting one, by the energy transforming unit enclosed reciprocating volume which entirely or partly passes through the at least one conversion module (2a-d, 56, 64, 73, 80, 81, 87, Cm). The reciprocating volume can comprise a non-compressible fluid arranged to forward the incoming forces into a reciprocating fluid movement over the at least one conversion module (2a-d, 56, 64, 73, 80, 81, 87, Cm) and/or the reciprocating volume can comprise at least one mechanical force transmitting arrangement adapted to the at least one conversion module. The unit further comprises a compact central unit (1 a-q) which at least partly encloses the at least one conversion module.