Question

4. Fig. 7 shows a shaft assembly used in gear reducer, where a pair of bearings radial forces on gears 1 and 2 are Fri=12600N, FR2-14400N; the axial forces on gears FATSOON; the pitch circle diameters of gear 1 and 2 are di-200mm and droom The revolution of shaft is n-600 r/min, the application factor ar=1.5. (The basic dyna C = 71kN, e0.4, the induced axial force Fi - F/3.0. If F/F>e, X -0.4, Y-1.5, and 1, Y 0; Note: F. and Fare axial force and radial force on one bearing) (13 points) (1) Explain the meaning of the bearing designation 30209; (2) Calculate the bearing life in hours; (3) This reducer will work 8 hours one day and 200 days one year. If the required to your opinion about this selection of rolling bearings. carings 30209 is used. The n gears are FX-600N. 700mm, respectively. basic dynamic load rating -1.5, and if FF. Se, X = required life is 8 years, give 50 50 50 Fig. 7

Answer 1

(Given data'- FRI= 12 G00N F Rz= 1440ON FAI= 600N FA2= 1500N d= 2 00 d2 = 10omm mm 600Tpm C=71 KN Fa ze Fr 0.4 If faspe Fr Soln -> =2 30209 Destanation. 45mm Bore dia 1ignt heignt Beaming. 2nd semer 2. Contact Rolling 1ife in hout 1x 12600 t 12600N

xF,+Y FAz PL= 1 x 14400 tox 150o P2 14400 P Pt P2 = 12600 t 14400 27000 3. L10= Bearing 1fo in million revalution L1o = 71000: 27000 18. 18 milion revoluhong Lion Lio x io 6ox 18.18 x lo6 Go x 600 50s houne

200 day! Lion for 8 his & lion= 12800 hrs Lio= X 12800 106 460.8 million revoluhion Lia 13. Li0) 13 460.8 27000 208.54 kN