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Rules
Variables SheetInput Name Output Unit Comment
6 P diametral pitch, it is a standard size, table13-3 [teeth/inch]
34 N_s number of teeth sun piniond_s 5.666667 pitch diameter of sun pinion [in]
31 N_p number of teeth planet pinionsd_p 5.166667 pitch diameter of planet pinions [in]
96 N_r number of teeth internal geard_r 16 pitch diameter of internal gear [in]V 13351.768778 pitch line velocity [ft/min]
9000 n_s sun pinion speed [rev/min]W_t 7909.064466 total transmitted load [lbf]
32000 Hp shaft horsepower to the sun pinion [hp]W_r 2705.059362 radial component [lbf]
20 φ_n normal pressure angle, choose a standard20 degrees
W_a 3140.936752 axial component, thrust load, cancel fordouble helical [lbf]
25 ψ helix angle, ASSUME choose 25 degrees,thats what prob 14-39 has
W 9286.746430 total force [lbf]ratio 2.823529 gear ratio & speed ratio, sun to ring
2300 C_p elastic coefficient, steel on steel, table 14-5,[psi]
1 C_a application factor, ASSUME, sec 14-8C_v 1 AGMA dynamic factor, eq 14-27
1 C_s size factor, MOST OFTEN UNITY, section14-10
2.5 F face width [in], ASSUMED1.2 C_m load distribution factor, table 14-6, ASSUME
accurate helical1 C_f surface condition factor > 1 for obvious
defects, section 14-9I 0.135904 geometry factorφ_t 21.880233 transverse pressure anglem_F 2.226455 face contact ratio, should be > 2 eq 14-19p_x 1.122861 axial pitch [in], eq 13-13m_N 0.606793 load sharing ratiom_G 0.911765 speed ratioAA 106 used in dynamic factor eq
June 21, 2012 5:33:14 PM5 7Page of TURBOFANPLANETS.TKW
Input Name Output Unit Comment
BB 0 used in dynamic factor eqQUALITY MUST BE AT LEAST 12 !!!
12 Q_v transmission accuracy-level #, quality #,ASSUME 12, sec 14-7reference aerogear.com, manufacturing,sizes
p_N 0.445923 normal base pitch [in], eq 14-24Z 0.773563 length of line of action in the transverse
plane [in]p_n 0.474542 normal circular pitch [in], eq 13-12p_t 0.523599 circular pitch [in], eq 13-4r_s 2.833333 pitch radius sun [in]a 0.166667 addendum distance [in], p 266r_bs 2.629234 sun base radius [in]r_p 2.583333 pitch radius planet [in]r_bp 2.397243 planet base radius [in]n_p 9870.967742 not needed for this code, planetary rpm's for
Jeremy's codeσ_c 161484.850496 contact stress from total force, [psi]
---------------------------------------------------------215000 S_c surface fatigue strength, table 14-4,
ASSUME intermediate value, [psi]C_L 0.853043 life factor, average of upper & lower limits fig
14-8, p340C_L_high 0.910418 upper limit for N_life > 10^7C_L_low 0.795669 lower limit for N_life > 10^7C_H 0.999939 hardness ratio factor
1 C_T temperature factor, sec14-15, ASSUME T <150 F
1 C_R reliability factor, table 14-7 ASSUME 99%N_life 592258064.51612
9life cycles
A .00069 part of hardness factor eq630 H_B_s Brinell hardness of the sun pinion,
ASSUMED AISI 9310 steel630 H_B_p Brinell hardness of the planets, ASSUMED
AISI 9310 steelReference gear materials paper we weregiven
σ_c_all 183393.156207 allowable contact stress, [psi]------------------------------------------------------------------
n_surface 1.135668 surface fatigue factor of safety------------------------------------------------------------------
1000 hours Design gear to last 1000 hours------------------------------------------------------------------
K_a 1 application factor
June 21, 2012 5:33:14 PM6 7Page of TURBOFANPLANETS.TKW
Input Name Output Unit Comment
K_v 1 dynamic factorK_s 1 size factorK_m 1.2 load-distribution factor
.535 J_75 geometry factor for 75-tooth mate, bending,fig 14-5, p335
.962 J_mod modifying factor for other than 75-toothmate, fig 14-6
J .51467 modified geometry factor for use in theequation
σ_bend 44257.690680 bending stress [psi]------------------------------------------------------------------
70000 S_t_table bending strength, table 14-3,carburized/case hardened, [psi]
S_t 49000 corrected bending strength for completelyreversed bending [psi]
K_L 0.911423 life factor, average of upper & lower limits fig14-9, p341
K_L_high 0.946335 upper limit for N_life > 10^7K_L_low 0.876512 lower limit for N_life > 10^7K_T 1 temperature factorK_R 1 reliability factorσ_bend_all 44659.750655 allowable bending stress [psi]
------------------------------------------------------------------
n_bending 1.009085 factor of safety pertaining to bending
June 21, 2012 5:33:14 PM7 7Page of TURBOFANPLANETS.TKW