| 摘要 |
PURPOSE:To aim at reducing mechanical losses in the gaps between tooth surfaces, bearings, supporting rotors, etc., by forming a forward surface first crank in a female rotor, in a shape of a parabolic curve having a focal point positioned inside of a pitch circle to reduce an operating pressure angle on the crank. CONSTITUTION:The shape of a forward surface first crank 25 in a female rotor 23 having an addendum, extending between points 29 to 30, is exhibited by a parabolic curve expressed by y<2>-4a(x-E); where E is the distance between the rotational axis 4 and the point 29; and (a) is the distance between the point 29 and a focal point 31 existing on the line connecting between both rotational axes in the pitch circle 11, on the x-y coordinates. with this arrangement, the radial force or the pressure angle between both surfaces in the vicinity of the point 30 on the forward surface first crank 25 which transmits power when a male rotor 26 drives the female rotor 23, may be reduced. As a result the surface pressure between the power transmitting tooth surfaces in the vicinity of the point 30 and in the vicinity of the point 36 on the forward surface first crank 28 of the male rotor 26, may be reduced to reduce mechanical losses. |
