1. The actual effective interference calculation formula △dyu003d△dG△d —— Nominal interference G —— Flattening size of interference fit For example: Bearing inner diameter φ40 shaft φ40 Nominal interference value is +25μm after compression 1/3 After that, the actual effective interference is +17μm. The flattened size G of the interference fit is 1μm when the surface roughness is 0.8. 2. Estimation formula for radial clearance reduction ①Bearing inner ring and steel solid shaft △ju003d△dy*△j——inner ring raceway rib diameter expansion (μm) d——bearing inner diameter nominal size ( mm) h——diameter of inner ring raceway rib (mm) ②Bearing inner ring and steel hollow shaft △ju003d△dy*F(d)F(d)u003d *d1——inner diameter of hollow shaft (mm)③ Bearing outer ring and steel solid shell △Au003d△Dy*△A——diameter expansion of outer ring raceway rib (μm) △Dy——actual effective interference of shell hole diameter (μm) D——outside bearing Nominal size of diameter (mm) H—— outer ring raceway rib diameter (mm) ④Bearing outer ring and steel thin-walled shell △Au003d△Dy*F(D)F(D)u003d *F——bearing seat Outer diameter of the housing ⑤Bearing outer ring and gray cast iron housing △Au003d△Dy[F(D)-0.15] ⑥Bearing outer ring and light metal housing △Au003d△Dy[F(D)-0.25] 3. Because of the inner and outer ring The amount of clearance reduction caused by the temperature difference δt u003d αΔt Do (mm) where α—the expansion coefficient of the bearing steel 1.12×10 (1/℃) Δt—the temperature difference between the inner and outer rings (℃), Δt u003d T Inner-T Outer Do — Outer ring raceway diameter (mm). 4. The reduction of radial clearance △j+△A+δt5. According to the reduction of radial clearance, select the clearance range in the clearance group. For example: bearing model: 22332, the inner ring is subjected to a local heavy load and moves axially with the shaft sleeve, and g6 is used as the fit. The outer ring is subjected to cyclic load, and is tightly matched with the housing hole, and is matched with P6. Inner ring: φ160 axis: φ160 maximum nominal interference △d u003d11, Gu003d2.5, the actual effective interference △dyu003d4.8d/hu003d160/191≈0.838△ju003d△dy*d/hu003d4.8 *0.838≈4 Outer ring: φ290 shell hole: φ290 maximum nominal interference △D u003d79, Gu003d5, the actual effective interference △Dyu003d48H/Du003d258/290≈0.89△Au003d△Dy*H /Du003d48*0.89≈43 Assume that there is no other heat input. δt u003d0 means the radial clearance reduction: △j+△A+δtu003d4.8+31+0u003d35.8μm According to the range of the clearance, select 2 groups of clearances (60~110μm)