Floor grinding machine

A floor grinding machine comprising a supporting frame, a grinding unit attached to the supporting frame, and a drive unit connected to the grinding unit,

• where the grinding unit comprises an upper housing, a lower housing rotatably arranged in relation to the upper housing, and a planetary drive system connected to the drive unit,
• where the upper housing comprises a top plate and a first side wall projecting downwards from the top plate in an axial direction (AX),
• wherein the lower housing comprises a bottom plate and a second side wall, where one or more grinding disks adapted for holding a tool are rotatably attached to the bottom plate, where the planetary drive system is arranged to rotate the lower housing and the one or more grinding disks respectively,
• where the first side wall is coaxially arranged in relation to the second side wall, and where the first side wall in the axial direction (AX) at least partly is overlapping the second side wall, and
• wherein a gap is formed in a radial direction (R) between the first side wall and the second side wall, and where a sealing element is arranged in the gap.