Abstract: In a shaft (19) having outer teeth (18) for transferring torque between hydraulic machines (1, 2) arranged coaxially behind one another, especially hydraulic pumps of a steering device, in which an inner wheel (7; 8) provided with teeth (9; 10; 15; 16) on the inside and outside moves around the inside of a toothed ring (3; 4) having inner teeth (5; 6) and engages with the teeth (5; 6) of the toothed ring (3; 4), and the teeth (18) of the shaft (19) engage without relative rotation in the inner teeth (15; 16) of the inner wheels (7, 8), in order to simplify manufacture and assembly of the shaft and to avoid noise, the thickness of the teeth (18) of the shaft (19) or of the inner teeth (15; 16) of the inner wheels (7, 8), measured on the reference circle, is greater than the width, measured on the reference circle, of the gaps into which those teeth (18; 7; 8) engage, with the result that the flanks of the teeth (18) of the shaft (19) come into contact securely with the flanks of the inner teeth (15; 16) of the