1. Fit and clearance of high-speed Timken bearing since the machine tool Timken bearing and high-speed Timken bearing shall meet the requirements of both high-precision Timken bearing and high-temperature Timken bearing, the following two points shall be considered when considering their fit and clearance:
(1) Size change and hardness change from normal temperature High Speed Timken Bearing to high temperature;
(2) The change of force system and shape caused by centrifugal force at high speed.
In short, under the conditions of high speed and high temperature, it is High Speed Timken Bearing difficult to maintain the accuracy and working performance of Timken bearing from the selection of fit and clearance.
In order to ensure that the raceway deformation of Timken bearing after installation is small, the interference High Speed Timken Bearing of interference fit cannot be too large, and the centrifugal force at high speed and thermal expansion at high temperature can offset the normal pressure on the mating surface.
Or relax the mating surface, so the interference must be calculated carefully on the premise of High Speed Timken Bearing considering the above two factors. The effective interference at normal temperature and speed may be invalid for high-speed Timken bearing.
If the contradiction between the calculation results is too large (usually only at ultra-high speed), only the dual lubrication measures of under ring High Speed Timken Bearing lubrication method and hydrostatic lubrication method can be adopted, and this scheme may make the DMN value of Timken bearing break through the 3 million mark.
When considering the clearance of high-speed Timken bearing, we should not only consider the above factors, but also consider the influence of the thermal elongation of the shaft on the clearance. Timken bearing is required to have clearance under the working state, that is, under the working temperature, and this clearance is formed under the condition of accurate alignment of the ball groove centers of the inner and outer rings.
As high-speed Timken bearings strive to reduce relative sliding and internal friction, do not use the method of relative dislocation of the inner and outer rings along the axial direction to adjust the clearance of ball Timken bearings.
When considering the fit interference and clearance of Timken bearing, we should pay attention to the characteristics that the material becomes soft and easy to deform at high temperature, and the possibility High Speed Timken Bearing of permanent deformation caused by multiple temperature changes from normal temperature to high temperature.
The high-speed Timken bearing requires the rotary system where the High Speed Timken Bearing Timken bearing is located to undergo precise dynamic balance.
The parts where the Timken bearing is installed on the shaft and seat hole shall have higher dimensional accuracy and shape and position accuracy than the general requirements, especially the coaxiality and the perpendicularity of the retaining shoulder to the seat hole or Journal. When considering these problems, Attention must also be paid to the high-speed and high-temperature factors during Timken bearing operation.
In order to overcome this contradiction, measures such as reducing surface roughness and improving surface strengthening can be taken to improve the support High Speed Timken Bearing stiffness, and hollow shafts can be used to reduce the system mass.