2. FUNCTION 2. FUNCTION 1) 1) ROTARY PART ROTARY PART When high pressurized oil enters a cylinder through port(a), which is the inlet of balance plate(16), hydraulic pressure acting on the piston causes axial force F. The pressure force F works via the piston(10) upon the return plate(9) which acts upon the swash plate(7) via an hydrostatic bearing. Force F1 perpendicular to swash plate(7) and force F2 perpendicular to cylinder center. Being transferred to the cylinder block(3) through piston, force F2 causes rotational moment at surroundings of cylinder.
Since cylinder block has 9 equidistantly arrayed pistons, rotational torque is transmitted to cylinder shaft in order by several pistons connected to the inlet port of high pressurized oil. When the direction of oil flow is reversed, rotational direction of cylinder is also reversed. Output torque is given by the equation. T = , q=Z · A · PCD · tan θ , F1 = , F 2 =F tan θ , S=PCD Ч tan θ Where p : Effective difference of pressure ( kgf/cm 2 ) q : Displacement ( cc/rev ) T : Output torque ( kgf · cm ) Z : Piston number (9 EA ) A : Piston area ( cm 2 ) θ : Tilting angle of swash plate (degree) S :
Piston stroke ( cm ) p Ч q F 2 Л COS θ 2-14 Low High pressure oil pressure oil F1 F1 F 16 7 9 10 3