Hydraulic switch valve and arm

The utility model discloses a hydraulic switch valve and arm, the hydraulic directional control valve group of the H bridge construction that the arm becomes including the arm axle, hydraulic power units that have the fluid pressure type bearing, by four hydraulic switch valvess, the case of hydraulic switch valve amounts to the lamination formula case that piece circular sheet stacked formation,and the P hydraulic fluid port sets up in the one end terminal surface of valve pocket, and actuator port sets up on the axial lateral wall of valve pocket, fluid pressure type axle contracting drawstogether bearing inner race and installs in the epaxial bearing inner race of arm, and bearing inner race has the annular groove, and the bearing inner race terminal surface is equipped with the convex second recess that distributes, and the annular groove bottom is equipped with the protruding muscle with second recess gas tightness looks sliding fit, and protruding muscle both ends are equippedwith the through -hole, hyd