Filter unit of cleaning machine, floor cleaning machine and operation method of floor cleaning machine

The invention relates to a filter unit for cleaning a surface made of a textile material, the filter unit being positionable as a whole on a cleaning machine (10) and removable as a whole from the cleaning machine (10), the filter unit comprising a housing (136), at least one first filter (146) and one second filter (148), the first filter (146) and the second filter (148) being arranged on the housing (136), the first filter (146) is a pre-filter of the second filter (148), and the first filter (146) is configured as a fluff filter. 提供一种过滤单元，其用于清洁由纺织材料构成的表面，其中，过滤单元能作为整体定位在清洁机(10)上并且能作为整体从清洁机(10)上取下，过滤单元包括壳体(136)、至少一个第一过滤器(146)和第二过滤器(148)，其中，第一过滤器(146)和第二过滤器(148)布置在壳体(136)上，第一过滤器(146)是第二过滤器(148)的预过滤器，并且第一过滤器(146)被构造为绒毛过滤器。