SE311500B - - Google Patents

Abstract

1,157,273. Hydraulic screw-type motors. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. July 14, 1966 [July 17, 1965], No.31617/66. Heading F1T. A hydraulic screw-type motor comprises a cylindrical rotor disposed within a cylindrical bore in a housing, the rotor being formed with two helical grooves of opposite pitch, the housing being provided with an inlet for high pressure medium in the region where the helical grooves adjoin. An outlet duct is provided in the housing at the opposite ends of the helical grooves. The width of the helical walls forming the helical grooves is small compared with the groove width, whilst the core ciameter in the region of one of the groove patterns is larger than the core diameter in the region of the other groove pattern. At the end of the groove pattern of larger core diameter, there is provided an axial thrust bearing to which hydraulic medium is supplied. In the embodiment shown the rotor 4 is formed with helical groove patterns 5 and 6 of opposite hand, the rotor being mounted in the housing 1 by means of an axial thrust bearing 9, 10, 11. Hydraulic fluid under pressure is supplied through ducts 2 and 3 to the centre of the rotor and then flows therethrough in opposite directions, the fluid discharging into annular grooves 7 and thence through outlet duct 8. The core diameter of the rotor a is greater than core diameter b. The ratio of the width c of the helical wall to groove width d is 0À1 while the ratio of the clearance e between the peak of the helical walls and the cylindrical wall of the housing to the clearance f between the core periphery and the cylindrical wall of the housing is 0À085. The pitch angle of the grooves is 0À25 radian. The output shaft 12 is formed with helical grooves 14 where it passes through the housing so as to prevent leakage. A tool such as a grinding wheel 13 is mounted on the shaft. The rotor is 18 mm in length and 6 mm in diameter and the effective power is 40 W and the speed is around 50, 000 R.P.M.