久久情操情在线免费播放

When digging a hole, the drill bit rotates around the vertical shaft and moves axially at the same time.  The soil is cut under the action of torque and axial force of the drill bit, destroyed and crushed under the action of extrusion and centrifugal force of the working blades, forming soil flowing pressure to the pit wall and rising to the surface along the page.  When the soil flow moves to the place where there is no pit wall blocking, the crushed soil is thrown around the pit due to centrifugal force to complete the whole digging process.