The tolerances of super-precision bearings comply with DIN 620 standards. The definition of dimensions and accuracy is as described in DIN ISO 1132. In order to ensure the full performance of the bearing and achieve very high processing accuracy, the size, shape and running accuracy of ultra-precision bearings are manufactured in accordance with the small tolerances specified in the standard: the shape and position tolerances also meet the corresponding accuracy levels. All super-precision spindle bearings and floating displacement bearings reach the P2 level, except for the B718 series, which reach the P4 level. All super-precision cylindrical roller bearings and two-way angular contact thrust ball bearings reach the P4 level. Higher precision levels can also be provided according to customer requirements UP grade precision cylindrical roller bearings. Hole measurement method d u003d nominal diameter (tapered inner hole: minimum diameter) d1 u003d nominal diameter of the large end of the tapered hole Δds u003d ds d in a single radial plane, the deviation of a single hole from the nominal diameter Δdmp u003d dmp d in a single radial In the plane, the deviation of the average hole diameter from the nominal hole diameter Δd1mp u003d d1mp d1 The deviation of the average diameter of the large end of the tapered hole from the nominal hole diameter Vdp u003d dpsmax dpsmin The variation of a single hole diameter on a single radial plane (Vdp is about out-of-roundness, conforming to DIN 620 standard) ; (Vdp/2 is approximately roundness, in line with DIN ISO 1132 standard) (measurement method is equivalent to measurement of out-of-roundness) Vdmp u003d dmpmax dmpmin The average aperture variation on different radial planes. Outer diameter measurement method D u003d Nominal outer diameter ΔDs u003d Ds D In a single radial plane, the deviation of a single outer diameter from the nominal outer diameter ΔDmp u003d Dmp D In a single radial plane, the deviation of the average outer diameter from the nominal outer diameter VDp u003d Dpsmax DpsminV variation of the outer diameter on a single radial plane (VDp is equivalent to out-of-roundness, in line with DIN 620 standard); (VDp/2 is equivalent to roundness, in line with DIN ISO 1132 standard) (measurement method is equivalent to out-of-roundness measurement )VDmp u003d Dmpmax The average outer diameter variation of Dmpmin in different radial planes. Width and height measurement method ΔBs u003d Bs B deviation of the width of a single inner ring from the nominal width ΔCs u003d Cs C deviation of the width of a single outer ring from the nominal width VBs u003d Bsmax Bsmin The amount ΔHs u003d Hs H is the deviation of the height of a single set of thrust bearing from the nominal height. Running accuracy measurement method Kia u003d Radial runout of inner ring of complete bearing Kea u003d Radial runout of outer ring of complete bearing Sd u003d End face runout of inner ring relative to the inner hole (axial runout) SD u003d Cylindrical surface of outer ring relative to outer ring reference plane The amount of tilt change (axial runout). Sia u003d End face run-out of the inner ring relative to the inner ring raceway (axial runout) of the complete set of bearing The axial run-out of the thrust bearing) Se u003d the wall thickness variation of the thrust bearing race (the axial run-out of the thrust bearing).