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发表于 2008-8-21 21:58:09
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来自: 中国山东聊城
9.螺旋角系数
1 A; L2 z" ~7 i- S) r: c2 t4 ZΖβ=(cosβ)^0.5=0.9935
5 d& b0 g3 |8 I. G S2 X10.单对齿啮合系数(根据表2.5-33)3 n T5 G! ~5 l0 O' _
ΖB=tanα′t/{[(da1^2/db1^2-1)^0.5-2π/Ζ1]*[(da2^2/db2^2-1)^0.5-(εα-1)*2π/Ζ2]}^0.5=1.0087) t: H! r: R9 O, D8 I
ΖD=1/ @, u" k' X! ^! \# x, P2 k9 [
11.寿命系数(根据表2.5-40)
8 b2 m7 h/ d6 R7 QNL1=n1*L=34800000000
) @ }' `" \3 Q Q5 L7 l ?NL2=NL1/u=216000000002 ~9 a( z F2 r T0 P
ΖNT1=(5*10^7/NL1)^0.0306=0.8185 U' \- y; O6 G. X: U
ΖNT2=(5*10^7/NL2)^0.0306=0.8305 H; M1 ] @7 ~
12.润滑剂系数(根据表2.5-36)% v. t. a) Q! M
σHlim1>1200 MPa,取σHlim1=1200 MPa,CZL1=σHlim1/4375+0.6357=0.910
J' w' _1 r4 i @ΖL1=CZL1+4*(1.0-CZL1)/(1.2+80/ν50)^2=0.9233
% {3 Y+ f6 S* a! [- C) \; IσHlim2>1200 MPa,取σHlim2=1200 MPa,CZL2=σHlim2/4375+0.6357=0.910
2 c* }4 @9 s2 `; Y* [7 V6 `4 f' mΖL2=CZL2+4*(1.0-CZL2)/(1.2+80/ν50)^2=0.9233
7 n' g! F5 ^* N3 F/ \& f( p5 D( b3 g13.速度系数(根据表2.5-36)
D0 `* c" L: X; Z- z& P: T3 ^σHlim1>1200 MPa,取σHlim1=1200 MPa,CZV1=0.85+(σHlim1-850)/350*0.08=0.930
. o% o0 k3 \- W$ o- |+ v# WΖV1=CZV1+2*(1.0-CZV1)/(0.8+32/ν)^0.5=1.0650# y2 ?/ l& C1 B- c
σHlim2>1200 MPa,取σHlim2=1200 MPa,CZV2=0.85+(σHlim2-850)/350*0.08=0.9302 t" x$ L/ r: l4 G4 v
ΖV2=CZV2+2*(1.0-CZV2)/(0.8+32/ν)^0.5=1.0650
) C8 ~, V+ j1 j5 p14.粗糙度系数(根据表2.5-37)
( P: c3 R' \6 z* G% W
' ]1 P& ?2 O5 h节点处曲率半径:ρ1=0.5*db1*tanα′t=33.126 mm, c6 G6 k; x2 l; ?+ ?& c: K
ρ2=0.5*db2*tanα′t=53.371 mm9 P! P8 S4 B5 U/ _/ c, V
9 I% E2 N3 \: C' u. V+ V+ G节点处诱导曲率半径:ρred=ρ1*ρ2/(ρ1+ρ2)=20.440 mm4 ^4 ?% H9 |# e6 r4 O4 [* J
3 ]9 W6 C- H w& f! I* t$ s
相对平均表面粗糙度:Rz10=(Rz1+Rz2)/2*(10/ρred)^(1/3)=2.521
1 E7 p8 ~: F* d) nσHlim1>1200 MPa,取σHlim1=1200 MPa,CZR1=0.32-0.0002*σHlim1=0.080; ^0 M. s8 {( {3 @
ΖR1=(3/Rz10)^CZR1=1.01406 \! J3 m4 b" f! |2 d/ n
σHlim2>1200 MPa,取σHlim2=1200 MPa,CZR2=0.32-0.0002*σHlim2=0.080
; m3 x' _* m* g" `& d [0 }ΖR2=(3/Rz10)^CZR2=1.0140
' a! K' G5 U+ q2 r' v15.齿面工作硬化系数
- k% ?$ G8 X# `0 R- c' [- FHB>470HBW,取HB=470
) ?4 a% k5 r) h; _$ i6 U4 E @, KΖW1=ΖW2=1.2-(HB-130)/1700=1# r# y% h3 S0 m( \* y9 R- z) d
16.尺寸系数(根据表2.5-41)0 }$ \% S S q$ Q$ m
ΖX1=1.0000
( _* k6 r5 c: @6 T+ ^. jΖX2=1.0000
7 ]; k! }4 P- t6 ^, e& m- Q+ a17.最小安全系数1 J. ]6 T& O7 q) k
# j& s) G4 S* v2 L2 x2 o" m根据表2.5-42,取SHmin=1.60,SFmin=2.00
; M) m- X# w& q2 s% s* X18.计算接触应力(表2.5-6)0 H# ?. Q, Z" f5 d7 B# c
бH0=ΖHΖEΖεΖβ[Ft/(d1*b)?(u+1)/u]^0.5=457.83 MPa8 D6 t/ Q9 ^$ d* C( D* ^% i
бH1=ΖB*бH0*(ΚAΚvΚHβΚHα)^0.5=693.96 MPa
. _* M1 v5 W" U- A- N% eбH2=ΖD*бH0*(ΚAΚvΚHβΚHα)^0.5=687.98 MPa
# U# V+ [9 t% G7 [19.许用接触应力(表2.5-6)+ ?" Z8 [, v1 b6 R# ?
бHP1=бHG1/SHmin=бHlim1*ΖNT1ΖL1ΖV1ΖR1ΖW1ΖX1/SHmin=688.59 MPa
$ p0 _" b5 E+ {5 N3 jбHP2=бHG2/SHmin=бHlim2*ΖNT2ΖL2ΖV2ΖR2ΖW2ΖX2/SHmin=698.69 MPa
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由以上计算可知:бH1>бHP1,小齿轮的接触强度不满足要求1 d; ^$ c/ O7 a$ B1 I
бH2≤бHP2,大齿轮的接触强度满足要求。
* P, ^0 F! X6 `1 J' \" o20.接触强度计算安全系数(表2.5-6)6 c6 _" C" \/ e" X( q
SH1=бHG1/бH1=1.598 x1 [7 _9 Z# G6 I" J
SH2=бHG2/бH2=1.62# D/ j6 I2 M7 O4 K, C
& M, K1 N7 y, Z* y$ v- I7 ?7 e
七、弯曲疲劳强度的校核
8 X" U) j) Z$ J0 {2 w1.齿向载荷分布系数
/ P; v* f, d1 N3 w$ y2 J6 hN=(b/h)^2/[1+(b/h)+(b/h)^2],b/h取大小齿轮中的小值。
% L0 _. D. h1 g7 _2 A3 VΚFβ=ΚHβ^N=1.2877. V+ e: D, T% A4 m: N; S I
2.齿间载荷分配系数(根据表2.5-44)2 h# P- i( g# I; i+ ~
ΚFα=ΚHα=1.0660
3 C+ O5 Z3 x9 |1 B, R3.齿形系数(根据表2.5-45)
! q9 F, s9 e# y9 i- d. m(1).小齿轮
9 d8 r- h1 {* ?6 ]2 C1 E z( RSpr1=pr1-q1
8 z6 e4 Z$ @& Y8 nE1=πmn/4-hfp1*tanαn+Spr1/cosαn-(1-sinαn)*ρfp1/cosαn=0.2252 mm7 D+ {7 ^* s9 t2 X' T9 [4 S$ F
G1=ρfp1/mn-hfp1/mn=-0.87002 a# s( k9 _9 c9 y2 m, P; k
βb=arccos{[1-(sinβcosαn)^2]^0.5}=8°41′11″
: @0 W& I/ R: F0 l& Q8 gH1=2/ΖV1*(π/2-E1/mn)-π/3=-0.9934
% A1 E. j. {/ hθ1=(2G1/ΖV1)*tanθ1-H1,得θ1=54°25′38″" z+ {$ p4 |7 e$ w
SFn1/mn=ΖV1*sin(π/3-θ1)+3^(1/3)*(G1/cosθ1-ρfp1/mn)=2.1886% C- Q# d9 }* C z6 f' M
ρF1/mn=ρfp1/mn+2*G1^2/[cosθ1*(ΖV1*cosθ1^2-2*G1)]=0.5058/ \) V( J9 B) A. Z- N2 c* }
εαV=εα/cosβb^2=1.8082 @$ A9 |& d6 G. P5 E& c7 W* j
dV1=mn*ΖV1=195.9580 mm
# S; C& M; M% h F2 hdbV1=dV1*cosαn=184.1403 mm2 K: O# q! y9 \9 f/ u
daV1=dV1+da1-d1=202.9580 mm
t6 {) Y9 g- f! p/ L# \2 v- C FdeV1=2*{[((daV1/2)^2-(dbV1/2)^2)^0.5-π*mn*cosαn*(εαV-1)]^2+(dbV1/2)^2}^0.5=196.5194 mm
' j' y$ v& O& G8 l9 IαeV1=arccos(dbV1/deV1)=20°26′42″9 Z/ @6 b# P s6 X: K! L: h2 v
γe1=(π/2)/ΖV1+invαn-invαeV1=1°32′50″3 F( P, E: n" x# D! ~) [2 E, s
αFeV1=αeV1-γe1=18°53′52″
/ K3 p* p4 g$ K- yhFe1/mn=[(cosγe1-sinγe1*tanαFeV1)*deV1/mn-ΖV1*cos(π/3-θ1)-G1/cosθ1+ρfp1/mn]/2=0.8806
/ w" m' V9 Y8 s; u- xУF1=6*(hFe1/mn)*cosαnFeV1/[(SFn1/mn)*cosαn]=1.1105
7 n) N6 b. S$ ^9 _; H! J2 j(2).大齿轮
# m# ^! o2 W1 @: X. n/ d$ pSpr2=pr2-q2. p2 e/ f% x) z" X5 O# M
E2=πmn/4-hfp2*tanαn+Spr2/cosαn-(1-sinαn)*ρfp2/cosαn=0.2252 mm- L4 ]9 l6 n: a4 e4 l* u1 c$ l, e
G2=ρfp2/mn-hfp2/mn=-0.8700
0 |, H* S- n a! yβb=arccos{[1-(sinβcosαn)^2]^0.5}=8°41′11″- e; e4 z% T: a; S; i9 L2 X7 o
H2=2/ΖV2*(π/2-E2/mn)-π/3=-1.0138
- ~9 Y& ~ w% G) ?9 Yθ2=(2G2/ΖV2)*tanθ2-H2,得θ2=56°25′17″
1 e5 `. X3 M, o# j, P! rSFn2/mn=ΖV2*sin(π/3-θ2)+3^(1/3)*(G2/cosθ2-ρfp2/mn)=2.2475
c- j# |9 f9 i# R6 u; W! L* D+ zρF2/mn=ρfp2/mn+2*G2^2/[cosθ2*(ΖV2*cosθ2^2-2*G2)]=0.47330 h& g: y" @& _" ?+ N( w% z
εαV=εα/cosβb^2=1.8082
& y8 Z+ `2 p3 j( c9 [; J" K4 wdV2=mn*ΖV2=315.7105 mm
# ^2 U3 t4 l/ m/ [2 F2 OdbV2=dV2*cosαn=296.6708 mm
, i! e) e- c' O' _1 w* YdaV2=dV2+da2-d2=322.7105 mm4 u, f) G! ^, `- x
deV2=2*{[((daV2/2)^2-(dbV2/2)^2)^0.5-π*mn*cosαn*(εαV-1)]^2+(dbV2/2)^2}^0.5=316.5102 mm; G: ^5 I/ P7 l0 d( @
αeV2=arccos(dbV2/deV2)=20°23′38″, |5 b8 ^9 W8 k) H) N! y
γe2=(π/2)/ΖV2+invαn-invαeV2=0°56′40″
4 s( M+ |! m0 ]- I: n6 h$ q* l0 CαFeV2=αeV2-γe2=19°26′59″' Z) W# t. C9 o7 D# {: A, f- g
hFe2/mn=[(cosγe2-sinγe2*tanαFeV2)*deV2/mn-ΖV2*cos(π/3-θ2)-G2/cosθ2+ρfp2/mn]/2=0.9094
& b; x! m% B, h0 G3 G* l. e: FУF2=6*(hFe2/mn)*cosαnFeV2/[(SFn2/mn)*cosαn]=1.0839
- q& w' p! U& n- p0 {; a8 ^- q+ g/ \9 A4.应力修正系数+ K- H$ T+ ^2 Y! c* x# v
2 Z& }) q$ F, b: q J齿根危险截面处齿厚与弯曲力臂的比值$ }9 q& y5 X& m6 T
L1=SFn1/hFe1
# m: B' v& j6 `L2=SFn2/hFe26 \1 G8 _! I9 R/ I" E
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齿根圆角参数; p) A2 |) P0 F1 J# m3 _$ }
qs1=SFn1/(2*ρF1)1 C. j' l4 H& O3 z+ i; ^9 ?. A4 f
qs2=SFn2/(2*ρF2)* X7 }8 T+ e, k* N% Q! h# X
УS1=(1.2+0.13*L1)*qs1^[1/(1.21+2.3*L1)]=2.1862 J R' b! j* O' G
УS2=(1.2+0.13*L2)*qs2^[1/(1.21+2.3*L2)]=2.27852 G: H7 M5 J4 Q0 u" g$ S
5.重合度系数% j/ Q g& p8 |( {& _1 h _+ T& _
Уε=0.25+0.75/εαV=0.66485 _& q, P. M8 | q+ h$ E$ _
原文来自:http://bbs.21mould.net/viewthread.php?tid=4141 |
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