Lawn mower

A lawn mower comprising:

• a housing including an opened bottom;
• a rotation shaft extending in a vertical direction of the housing and having a lower end positioned within the housing;
• a cutter blade provided for the rotation shaft, and accommodated in the housing;
• and
• a belt type continuously variable transmission provided in a working power transmission system from the drive source to the rotation shaft, the belt type continuously variable transmission capable of changing a reduction ratio of a driven pulley to a drive pulley in a continuous manner,
• wherein the cutter blade extends along a horizontal line which is perpendicular to the rotation shaft;
• the driven pulley includes a fixed sheave provided for the rotation shaft, a movable sheave which is displaceable relative to the fixed sheave in an axial direction, and a torque cam mechanism configured to partially convert a rotation force applied to the movable sheave into a thrust that presses a side surface of a V-belt;
• and
• the lawn mower further comprises:
• a flap provided for at least part of the cutter blade, the flap having a flap angle changeable along the horizontal line;
• a control force converter unit configured to convert a displacement force of the movable sheave relative to the fixed sheave in the axial direction into a control force that controls the flap angle of the flap;
• and
• a transmission mechanism configured to transmit the control force of the control force converter unit to the flap, and
• wherein the rotation shaft comprises a hollow shaft;
• and
• the transmission mechanism is accommodated inside the hollow shaft.