A milking robot for fully automatic milking of dairy animals comprises at least one movable part and a cylinder adapted to support movement of the part, which cylinder has a cylinder wall with an aeration opening and a cylinder rod slidable in and out of the cylinder, the cylinder wall at least one variable volume part, which volume part is free from pressure fluid connections for displacing the cylinder rod and is further arranged to remain substantially in pressure balance via said opening with an environment of the cylinder, wherein a gas collection device is connected to the cylinder wall around said aeration opening, which has a variable volume and which together with the variable volume part forms an airtight gas volume, wherein a gas collecting device is connected to the cylinder wall around said aeration opening, which gas has a variable volume and which together with the variable volume part s volume, the gas collection device having a minimum volume greater than zero. It is thus possible to keep the variable volume part at substantially ambient pressure, so that when the cylinder rod is slid in and out, unnecessary back pressure is created in the cylinder, which makes operation more reliable. Also, even with a leak in the gas volume, there will be less or no exchange of gas, dirt and the like with the environment, at least not via gaskets and the like, so that the cylinder will have a better service life and reliability.Een melkrobot voor het volautomatisch melken van melkdieren omvat ten minste één beweegbaar onderdeel en een cilinder ingericht voor ondersteunen van een beweging van het onderdeel, welke cilinder een cilinderwand met een beluchtingsopening alsmede een in en uit de cilinder schuifbare cilinderstang heeft, waarbij de cilinderwand ten minste één variabel volumedeel omgeeft, welk volumedeel vrij is van drukfluïdumaansluitingen voor verplaatsen van de cilinderstang en voorts is ingericht om via genoemde opening nagenoeg in drukevenwicht te blij
