1、中文3800字，1900英文单词，1万英文字符附录 A 英文资料 Research on Design of Planetary Gearbox Nanjing Artillery College RaoZhenggang Abstract The design and calculations of planetary gearbox are detailedly discussed in this thesis.The calculations of structure parameters,transmissionratio,torque of eac
2、h shaft,braketorque,lockingmoment,and transmission power are explained here.Hence,this paper is of much importance to the design of planetary gearbox of caterpillar vehicle,tank,artillery and engineering mechanics. Key words: Planetary gearbox Structure parameter Torque Power c)Clu
3、tch L locks internal gear rign b and swiveling jib H(see figure 3,c) When clutch L combines gear ring b and swiveling jib H into one whole,nb=nH.Then torque TA of input shaft A can transmit through two ways:one is to transmit to output shaft B through central gear a,planet gear g and swiveling
4、 jib H；the other is to B by central gear a,planet gear g,internal gear ring b and clutch L.At this moment,TA=Ta,TB=-TA and locking moment TL is equal to the torque of internal gear ring Tb,TL=Tb.According to formula (4-3),the locking moment TL is TL=Tb=pTa (4-11) From the formula above,w
5、hen central gear a inputs and swiveling jib H outputs,the locking moment TL of the first scheme is the lowest and the size is smaller.So as to 2K-H(A) planetary gearbox,the first scheme is more reasonable. (1)Suppose internal gear ring b inputs,swiveling jib H outputs(see figure 4),TA=Tb,TB=TH
6、；Let us discuss the locking moment T1 of friction clutch of three different locking pattern. a)Clutch L locks intermal gear ring b and centra gear a(see figure 4,a),that is na=nb=nH；then the planet bar becomes a whole and rotates.So TB=-TA,T1=Ta.According to formula (4-2),TL is: (
7、4-12) So, b)Clutch L locks central gear a and swiveling jib H(see figure 4,b),that is nH=na and TL=Ta.So TL is So, (4-13) c)Clutch L locks internal gear ring b and swiveling jib H(see figure 4,c),that is nH=nb and TL=Tb.Since the clutch L links input shaft A and output
8、 shaft B,locking moment TL is equal to the torque transmitted by shaft A,namely TL=Tb=TA.So the locking moment TL is TL=TA From the formula above,when internal gear ring inputs and swiveling jib outputs,locking moment TL of the first scheme is the lowest.So it is the best to adopt the first lo
9、cking scheme. After TL is calculated,the necessary control units can be adopted to obtain the friction clutch with smaller size.But,infact,the best locking scheme can't be always realized due to difficulty instructrualdistribution.Under this situation,the locking scheme should be adopted t
10、o get more compact structure of clutch and smaller size of the gearbox. 5 Calculation of efficiency of planetary gearbox As to multi-degree planetary geabox,the ratio of output power PB and input power PA is called the transmission efficiency of planetary gearbox.Namely, (5-1) Where,TA、
11、nAtorque and rotational speed of input shaft A； TB、 nBtorque and rotational speed of output shaft B. Ratio nA/nB=ip is kinematics transmission ratio；ratio-TB/TA=ip is dynamics transmission ratio.Since TB has contains the friction loss of planetary gearbox,puttingip and ip into formula(5-1),we
12、can get the famous M.A.Kpe-ec formula: (5-2) So the efficiency of each step of multi-degree planetary gearbox p is equal to the ratio of its dynamics transmission ratio ip and kinematics transmission ratio ip. As it is said above,its kinematics transmission ratio ip is function of charac
13、teristic parameter p of planet bar,that is: ip=f(p1、 p2、 p n) (5-3) According to the relation of power equation, p is equal to ip multiplying (H)x then the function of p is obtained: (5-4) Where,Htransmission efficiency of planet bar in relative motion.As to 2K-H(A) planet bar,H=Ha
14、gHgb=0.970.99=0.96 The equation of index xj is (5-5) j=1,2, ， n The mathematical meaning of sign is symbol. Index xj=1,its symbol is decided by (5-5)； if the value of sign is more than 0,sign is “+”， and xj=+1；otherwise,xj=-1。 6 Sample of the design of planetary g
15、earbox Suppose the transmission sketch of planetary gearbox of one certain caterpillar truck is shown as figure 5.Its degerrs of freedom is w=3,the number of steps is nd=4(three forwarding steps and one reverse step).Try to calculate (1) number of control units m,number of planet bars k and nu
16、mber of basic components n0；(2)transmission ratio ip of each step；(3)torque T,brake moment T2 and locking moment TL of each component；(4)transmission defficiencyp of each step. Solution:(1)Calculation of the numbers of control units m,planet bars k and basic components n0. When degree of freedom w=3,the number of control components m can be calculated through formula (2-6,a),that is
