d=z*mdf=(z-2*h-2*c)*mda=(z+2*h)*mdb=d*cos(angle)渐开线方程r=db/2angle=t*45x=r*cos(angle)+pi*r*angle*sin(angle)/180y=r*sin(angle)-pi*r*angle*cos(angle)/180z=0 柱坐标的r=db/2/cos(t*55)theta=(tan(t*55)*180)/pi-t*55z=0