Calculation of joint fits of elastic sleeve-pin couplings with shafts

Abstract

The causes of defects in the connections of elastic pin-sleeve couplings with shafts are analyzed. It was revealed that such defects as the wear of the mounting holes of the half-coupling and the bearing of the keys and grooves on the shaft and in the holes of the half-coupling are due to the lack of tightness in the shaft-coupling connection. An analysis of the standards for the manufacture of couplings and shaft ends showed that most of the recommended fits would not provide the specified durability of the joint due to the presence of gaps and small interferences, at which there would be a relative movement of the surfaces of the mating parts. A technique is developed for selecting fits for joints of elastic pin-sleeve couplings with shafts to increase their reliability and service life. The technique was tested on the example of calculating the fit of half-couplings on shafts for H 090.40 gearboxes, depending on the method of their assembly. As a result of calculations Ø50H8/v7 and Ø50H8/u8 fits were obtained, each of which differs from that recommended by the standard. Ø50H8/v7 fit has high interference and guarantees no twisting when transmitting torque. It is the most expedient to use the Ø50H8/u8 fit, obtained by assembling by heating the bushing, since it is more stable in the range of tightness with a lower accuracy of shaft processing and, therefore, the cost of shaft processing will be lower. Keywords: elastic pin-sleeve coupling, tightness, fit, limit tightness, fit tolerance, torque. metr@rgau-msha.ru