US Patent 7188472 Method and hydromachine for controlling a displacement

The invention concerns a method and a hydromachine with a commutation device and with expanding and contracting pressure chambers passed by fluid and formed by displacement arrangements. With the method and the hydromachine, it is endeavoured to control a displacement in the hydromachine to keep pressure fluctuations small. For this purpose, the hydromachine has a group of devices, comprising a commutation device and at least two displacement devices, at least two of the devices being adjusted in relation to each other.