Vacuum cleaning tool with pear-shaped turbine chamber

A vacuum cleaning tool for a vacuum cleaning device, the vacuum cleaning tool comprising:

• a housing (4) having a partition (13) dividing an interior of the housing (4) into a brush chamber (5) and a turbine chamber (6), wherein the brush chamber (5) has a bottom (8) and vacuum slot (9) arranged in the bottom (8), and wherein the partition (13) has an intake window (14);
• a vacuum connector (23) connected to the housing (4) remote from the brush chamber (5), wherein the vacuum connector (23) has an outlet window (24);
• a working roller (11) arranged in the brush chamber (5) perpendicularly to a working direction (7) of the vacuum cleaning tool and having a peripheral portion (10) projecting from the brush chamber (5) through the vacuum slot (9) to the exterior of the housing (4);
• an air turbine (15) arranged in the turbine chamber (6) and configured to drive in rotation the working roller (5);
• wherein the air turbine (15) has vanes (20) arranged in an annular vane arrangement (21) with a vane-free center (50), wherein between the vanes (20) free flow paths (22) are provided extending toward the vane-free center (50);
• wherein a vacuum air flow (19) enters the brush chamber (5) via the suction slot (9), flows from the brush chamber (5) through the intake window (14) into the turbine chamber (6), flows within the turbine chamber (6) from the intake window (14) to the outlet window (24) through the vane-free center (50), and exits from the turbine chamber (6) through the outlet window (24);
• wherein the turbine chamber (6) has an intake cross-section (33) measured at the partition (13) in a direction transverse to a flow direction of the vacuum airflow (19) and a outlet cross-section (30) measured at an end (47) of the turbine chamber (6) facing the outlet window (24), wherein the intake cross-section (33) is greater than the outlet cross-section (30);
• and
• wherein intermediate cross-sections (32, 32′, 32″) of the interior of the turbine chamber (6) decrease in a direction toward the end of the turbine chamber (6) facing the outlet window (24) such that the turbine chamber (6) tapers toward the outlet cross-section (30).