7014 bearing 25° contact angle is compared with 17° contact angle

7014 bearing 25° contact angle is compared with 17° contact angle

Technical Exchange

Subject: 7014 bearing 25° contact angle is compared with 17° contact angle.

Current situation in Europe market: mostly use two kinds of 7014 bearings, which would be 25° contact angle and 15° contact angle for machining center's spindle Considering of the demands of axial rigidity and radial rigidity, most of spindles on machining center will be used 7014 bearing with 25° contact angle.

TIMG's point of View: For the machining performance of the machining center s spindle, we prefer to have sufficient cutting performance in radial direction.

Therefore stable and sufficient radial rigidity, is a necessary condition we need to meet with.

When we compare 25° contact angle bearing with the 17° contact angle bearing, we find, when 25° contact angle bearing is at axial rigidity of 33 kgf/um, the radial rigidity is only equivalent to the radial rigidity of the 17° contact angle bearing with an axial rigidity of 21.6 kgf/um. 

When the spindle is done the cutting, the cutting force is transmitted from rotating period and fixed period through the rolling element; the upper limit of the cutting force is different for the big ball and the small ball while transmission, which can be easily found according to the theoretical analysis. The upper limit of the transmission of the large ceramic ball in cutting force is more than twice that of the small ceramic ball, so the advantage of the large ceramic ball during cutting can be clearly seen.

Therefore, we recommend that the axial stiffness value shall be controlled around 22kgf/um, which can make the 17° contact angle bearing demonstrate better than the 25° contact angle bearing in cutting performance.