16 3 d Intenational Confeence on Vehicle, Mechanical and Electical Engineeing (ICVMEE 16 ISBN: 978-1-6595-37- The Analyi of the Influence of the Independent Supenion on the Comfot fo a Mine Tuck JINGMING ZHANG, JINHUA ZHANG, LEI CHEN AND JING PEI ABSTRACT In ode to olve the poblem that the low peed and diving fatigue of mine tuck caued by it poo buffe and damping of the upenion, the hydo-pneumatic independent upenion i adopted intead of the taditional leaf ping dependent upenion fo the mine tuck in thi pape. On thi bai, the mathematical model of the hydo-pneumatic ping i etablihed; ubequently the kinetic model of the upenion ae built in MATLAB/Simulink; then the comfot tet of the upenion fo the leaf ping and hydo-pneumatic ping ucceively; The eult how that the hydo-pneumatic ping can impove the comfot of the mine tuck compaed to the leaf ping, conequently enhance the tuck peed and alleviate the diving fatigue. PREACE Lage-tonnage tuck wok in a hotile envionment, howeve adopting hydopneumatic upenion can damatically alleviate impact, educe bump, impove dive woking condition a well a the aveage peed [1-4]. In dometic, the intoduction to the pinciple and the imulation analyi of the hydo-pneumatic ping ae mainly pefomed, but many eeache ae qualitative not quantitative, o a ytematic and baic eeach on thi ping i cace but neceay. Hydo-pneumatic ping i egaded a one of the ideal upenion ytem, eeaching whoe nonlinea mechanic chaacteitic ha a ignificant impact on the analyi and optimization fo the comfot of vehicle. THE CHARACTERISTICS ANALYSIS O THE HYDRO-PNEUMATIC SPRING In the tavel poce fo mine tuck, the main facto which influence the comfot index of the font upenion ae tiffne and damping of the hydo-pneumatic ping, theefoe eeaching the tiffne and damping chaacteitic i needed. Jingming Zhang, Jinhua Zhang, Lei Chen and Jing Pei, School of Automotive Engineeing, Habin Intitute Technology, Weihai 64, China
Stiffne chaacteitic of the hydo-pneumatic ping. When the main tuck i fully loaded, the patial fequency of the font upenion i equied to be 1.5~.1Hz. Taking the engine diplacement effect on the patial fequency into conideation, the patial fequency of the font upenion i elected Hz, and the elf-exciting fequency of the hydo-pneumatic ping i elected 1.8Hz.when the mine tuck i in the fully loaded equilibium poition. Othe paamete ae hown in table 1. Table 1. Hydo-pneumatic ping paamete. paamete value paamete value Oil cylinde oute diamete Ai cylinde inne diamete 9 D 1 (mm D (mm 11 Ai cylinde ectional aea Oil cylinde ectional aea S q (mm 95 S y (mm 64 Oil and ai cylinde aea atio α.67 Abolute peue p (MPa 15.8 Ga educed height H(mm 6 Adiabatic coefficient 1. Sping oientation angle γ( Self-exiting fequency n(hz 1.8 Oil denity ρ(kg/m3 9 low coefficient C.6 Damping hole diamete d1(mm 5 Check valve diamete d (mm 5 When the mine tuck i in the fully loaded equilibium poition, the abolute peue of the hydo-pneumatic ping i p = +.98 (1 S y N. In equation (1, i the load foce exeted on the ingle hydo-pneumatic ping, Accoding to the fequency chaacteitic equation: 1 gα co γ n = ( π H The initial ga educed height (m i deived a equation (3: H gα co γ = (3 4π n When the piton i in a tatic equilibium poition, the mechanic equation ae a follow: = p S p = p = p (4 1 y 1 g The elationhip between the main piton diplacement z and the float piton diplacement z i
S z = S h (5 y q Accoding to the themodynamic tate equation of the ga chambe: p V g t = p V (6 when the upenion vibate gently, the tate vaiation of the ga can be een a a poce with contant tempeatue, then =1.;When the upenion vibate haply, the tate vaiation of the ga can be een a a poce with themal iolation, then =1.3. om equation (5 and (6, equation (7 can be deived a: Then g ( p H h = p H (7 = p A 1 ( 1 α z / H (8 Equation (8 denote the tatic load chaacteitic of the hydo-pneumatic ping, the deivative of with epect to z mean tiffne coefficient of the hydopneumatic ping K K d p Aα / H = = dz 1 / 1 + 1 ( α z H (9 om equation (9, the elationhip between the tiffne K of the hydopneumatic ping and the main piton diplacement z can be hown in figue. igue illutate that the elationhip between K and z (namely the dynamic deflection of the upenion i nonlinea, and that the tiffne in the compeion toke i lowe than that in the extenion toke, which can atify the cuhion equiement when the mine tuck i diven to the ough oad. Stiffne /(N/m igue 1. The tiffne chaacteitic cuve of the hydo-pneumatic ping.
Damping chaacteitic of the hydo-pneumatic ping. When duing the actual opeation of the mine tuck, the piton of the hydopneumatic ping wok at a lowe fequency ection and the lubication between piton and cylinde i favoable, o the tiffne of the ping mainly come fom the check valve and the damping hole. Unde the condition that the oifice i a thin wall hole, the damping foe of the hydo-pneumatic ping in the extenion toke and compeion toke can be expeed a equation (1: c 3 ρ AA x, x > C A1 = 3 ρ AA x, x C ( A1 + A (1 In the equation (1, AA i annula cavity aea,mm ; ρ i oil denity,kg/m 3 ; C i flow coefficient; A 1 i damping oifice thottling aea,mm ; A i check valve oifice aea,mm ; ẋ i the piton peed,m/. The equation (1 can be ewitten into a unified fom uing ign function gn(x a equation (11 c = ρ A x 3 A ( ( C A A x 1 +.5.5ign (11 The deivative of c with epect to ẋ denote the tiffne coefficient C of the hydo-pneumatic ping C 3 dc ρ AAx = = dx C A1 + A.5.5ign x ( ( (1 om equation (1, the elationhip between C and ẋ can be plot in figue 3. igue 3 indicate that the elationhip between C and ẋ i nonlinea, and the lope of the C in the extenion toke exceed that in the compeion toke, which mean the inceaing ate of the tiffne in the extenion toke i much geate, atifying the vibation damped equiement when the mine tuck i diven off the ough oad. THE ESTABLISHMENT O 1/4 SUSPENSION DYNAMIC MODEL Accoding to the actual opeation of the mine tuck, the following hypothee ae popoed when the two degee of feedom dynamic model fo the 1/4 font independent upenion i built: vetical vibation i conideed only;nonlinea
facto ae neglect;mine tuck i diven at a contant peed,and tie keep contact with the oad all along; The font and the eal ma of the body keep independent with each othe. The built dynamic model i illutated in figue 3, which contain two degee of feedom, namely the vetical movement of upended ma and unupended ma. In the figue 3, Z and Z w denote the vetical diplacement of the upended ma and the unupended ma epaately (upwad vetical movement i poitive; K and C denote the tiffne and damping of the hydo-pneumatic ping epectively; m i upended ma; m w i unupended ma; Kw i the tiffne of the tie; Z i the oad diplacement input (upwad vetical movement i poitive. igue. The damping of the hydo-pneumatic ping. m z K C mw zw Kw z igue 3. Dynamic model of 1/4 upenion. Accoding to figue 3, the diffeential dynamic equation of the upenion can be lit a follow: ( ( m z = K z z + C z z (13 w w ( ( ( m z = K z z K z z C z z (14 w w w w w w whee z w = z z w i the dynamic deflection of the upenion and z w = z z w i the dynamic defomation of the tie. Z w, Ż S, Zw and Ż w ae taken a the tate vaiable of the ytem, namely X [ z z z z ] T can be expeed a equation(17 =,then the tate pace expeion w w w
z w 1 1 zw z K / m C / m C / m z = + z w 1 z w 1 zw K / mw C / mw K w / mw C / mw z w [ z ] (15 whee ż (vetical acceleation of the body, upenion and K w z w z w (dynamic deflection of the (dynamic load of the tie ae taken a the output vaiable, then the 1/4 upenion ytem output equation can be expeed a equation (18 zw z K / m C / m C / m z z w = 1 z w Kwz w Kw z w (16 When the oad excitation i exeted to the ytem, the yielded output [ ] T Y = z z K z can be een a the comfot indexe fo the upenion of the mine tuck. w w w COMORT INDEX SIMULATION O HYDRO-PNEUMATIC SPRING AND LEA SPRING In ode to compae the influence on the comfot index of the mine tuck fom the hydo-pneumatic ping and leaf ping, thee two kind of dynamical model ae etablihed in MATLAB/Simulink. On account of the nonlinea pefomance of the hydo-pneumatic ping, it tiffne and damping ae detemined fom the equation (9 and (1, while thoe of the leaf ping ae contant and the paamete ae fom the manufactue of the efeence tuck. D level oad i choen a the oad excitation input, then the imulation eult of the influence on the comfot index of the mine tuck ae yielded a figue 4 ~6, and the comfot index value ae collected in table 3. body vetical acceleation m/ mm upenion dynamic eflection ( 1.5 -.5 hydo-pneumatic ping leaf ping 4 6 8 1 ( time ig.4 Body vetical acceleation compaion ( 1-1 hydo-pneumatic ping leaf ping 4 6 8 1 ( time igue 5. Supenion dynamic eflection compaion.
tie elative dynamic load 1-1 hydo-pneumatic ping leaf ping Comfot index of upenion Body vetical acceleation (m/ Supenion dynamic eflection (mm Tie elative dynamic load 4 6 8 1 ( time igue 6. Tie elative dynamic load compaion. Table 1. Thee Scheme compaing. Value type Valid value Valid value Valid value Leaf ping Hydopneumatic ping Pefomance impovement.68.48 9.4% 86 6 7.9%.8.58 9.3% The above imulation eult indicate that when the D level oad excitation i exeted to the model, the hydo-pneumatic ping can make the body vetical acceleation educe 9.4%, upenion dynamic eflection educe 7.9%, tie elative dynamic load educe 9.3% which can lagely impove the upenion pefomance, thu enhance the ide comfot of the mine tuck. CONCLUSION Nonlinea hydo-pneumatic ping can make the comfot evaluation indexe of the independent upenion ignificantly deceae compaed to the leaf ping whoe tiffne and damping ae contant, thu the upenion pefomance i enhanced ubtantially. REERENCE 1. Zhang Junwei, Chen Sizhong, Zhao Yuzhuang, et al. Deign and Teting of a Hydopneumatic Supenion with Continuouly Adjutable Damping. Chinee Jounal of Automotive Engineeing. 15, No. 4, p. 8-89.. Zhou Changeheng, Gu Liang. Valve Paamete Deign and Chaacteitic Tet of Hydo- Pneumatic Sping. Automotive Engineeing, 8, No. 1, p. 53-56+9. 3. Yang Bo, Chen Sizhong, Wang Xun, et al. Reeach of Twin-accumulato Hydo-pneumatic Supenion. Jounal of mechanical engineeing, 9, No.5, p. 76-8. 4. Zou You, Yu an, Sun Tao. Simulation of Nonlinea Hydopneumatic Supenion fo Comfot. The compute imulation, 4, No. 1, pp. 157-159+11.