The invention to a valve unit (1) for a synthetically commutated fluid working machine (51), comprising a valve body (19,57), a movably arranged valve unit (3) and a separate fluid flow influencing unit (13, 25, 31, 35, 46, 56). The fluid flow influencing unit (13, 25, 31, 35, 46, 56) comprises a fluid flow influencing means part (18) and an attachment means part (28, 34, 38) for mechanical connection with the valve body (19). The attachment means part (28, 34, 38) and the fluid flow influencing unit (18) are connected to each other by a connection means part (27, 30, 33, 40, 47). The circumferential extent of the attachment means part (28, 34, 38) is larger as compared to the circumferential extent of the connection means part (27, 30, 33, 40, 47).