IMPACT OF THE TRACKED VEHICLE TURNING MECHANISM ON THE ENGINE POWER REQUIRED IN TURN

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1 1st Intenational Confeence on Advanced Technologies fo Develoing Counties Setembe 12-1, 2002 Slavonski od, Coatia IPACT OF THE TACKED VEHICLE TUNING ECHANIS ON THE ENGINE POWE EQUIED IN TUN V. Stojković, E. azijanac and. Jakočić Keywods: tacked vehicle, tuning mechanism, engine owe euied in tun, elative fixed kinematic tuning adius 1. Intoduction The tun of a tacked vehicle is accomlished by changing the winding seed of one of its tacks with elation to the othe, with simultaneous fomation of diffeent tactive foces on each tack [1,]. Duing the tun of the tacked vehicle thee is total incease of the movement dag, causing inceased engine and tansmission loads. The engine and tansmission load of the tacked vehicle deend to a geat extent also on the size of the so-called kinematic tuning adius ( ). The kinematic tuning adius is the tuning adius which is ealised with fixed tansmission elation of the kinematic chain to the inne tacks and without the sliding of fictional elements in the tuning mechanism [1,]. This ae analyses the imact of the tye of the militay vehicle tuning mechanism on the engine owe euied fo the tun and the efficiency coefficient of the tuning mechanism. Paametes ae defined, descibing elative change in the engine owe euied fo the tun and the change of efficiency coefficient of the tuning mechanism deending on the elative tuning adius. ased on the efomed analysis, ecommendations ae ovided fo the selection of the kinematic tuning adius. 2. Definition of Paametes fo Analysing the Tun The tun of a tacked vehicle on a hoizontal suface (Figues 1 and 2) is analysed with the tuning adius () within the inteval fom the tun aound the inne tack to the tun with a fee tun adius (F 1 = 0), with the following assumtions and estictions: the imact of the centifugal foce is neglected; the tack width and the vehicle weight eual one ( = 1, G = 1). L F 2 2 C 1 c F 1 Figue 1 Foces and toues on a tacked vehicle in tun 1

2 Figue 1 shows foces and toues acting on a tacked vehicle: 2 = esistance to ectilinea motion on the oute tacks, 1 = esistance to ectilinea motion on the inne tacks, F 2 = tactive foce on the oute tacks, F 1 = baking foce on the inne tacks, c = tuning esistance toue. esistances to ectilinea motion 1 and 2 and the tuning esistance toue c ae detemined by the following exessions [1,]: 1 = 0.5 f G, (1) 2 = 0.5 f G, (2) µgl c =, (3) µ max µ =, () ρ whee: f = ectilinea motion esistance coefficient fo a aticula suface, L = length of the leaning at of the tacks, ρ = elative tuning adius ( ρ = ), µ = tuning esistance coefficient fo a aticula suface and a aticula elative tuning adius, µ = tuning esistance coefficient fo a aticula suface at ρ = 0.5. max Tactive foce on the oute tack F 2 and the baking foce on the inne tack F 1 can be detemined by the following exessions [1,]: F 2 = 2 + F 1 = 1 + c, (5) c. (6) v v 0 v 2 C v c ρ v 1 O Figue 2 Plan of velocities of tuning tacked vehicle 2

3 Figue 2 esents velocities of tuning vehicles and elative tuning adii of the tacked vehicles: v 2 = velocity of tacked vehicle on the oute tack, v 1 = velocity of the tacked vehicle on the inne tack, v c = velocity of the cente of mass of a tacked vehicle, v 0 = velocity of the oint on the vehicle which etains the same velocity in tun as in ectilinea motion, = kinematic aamete of the tuning mechanism (elative co-odinate of the oint on the vehicle with velocity v 0 ). Paamete is intoduced which satisfies the following condition [3]: ( ) = c. (7) Afte inseting exessions (1), (2) and (3) into the exession (7), the esult is: µ L =. (8) f The tem of elative fixed kinematic tuning adius ρ is intoduced: ρ =. (9) The owe euied to ovecome the total oute esistances in tun (P 0 ) is geate than the owe necessay to ovecome esistance in ectilinea motion (P ) [2,3]: P = ( ) v 0, (10) P 0 = P. (11) The engine owe euied to make the tacked vehicle tun (P ) is detemined accoding to the exession [2,3]: P = ( ) v 0 = P. (12) The coefficient of the elative engine owe euied in tun ( ) and the efficiency coefficient of the tuning mechanism ( η ) ae intoduced in the following manne [2,3]: = η = P = P P 0 ρ = + P, (13). (1) ased on the evious exessions it may be concluded that the coefficient of elative engine owe euied in tun and the efficiency coefficient of the tuning mechanism η ae vaiables deending on: motion esistance coefficient ( f ) of the gound on which the tun is ealised; elative tuning adius ρ ; elative fixed kinematic tuning adius ρ and kinematic aamete. Fo an ideal tuning mechanism = 1 = 1 would be achieved fo evey elative tuning adius. 3

4 3. Imact Analysis of the Tuning echanism Fo the analysis the tuning mechanisms have been selected that have the value = 0.5 [5,6,7,8]. The tun of the vehicle on the hoizontal sodded-gass suface is analysed with the assumed coefficients [1,] f = 0.06 and µ = 0.8. Gahical esentation of the calculation esults max of coefficients fo the vehicle T-3 is esented in Figues 3 and, fo the vehicle T- 55 in Figues 5 and 6, fo the vehicle VP -80 in Figues 7 and 8 and fo the vehicle -8A in Figues 9 and 10. 6,0 y 5,0 h,0 3,0 ρ 0 2,0 0, ρ 0 0, Figue 3 Coefficient of elative engine owe euied in tun fo T-3 Figue Efficiency coefficient of tuning mechanism fo T-3 6,0 y h 5,0 ρ 1,0 ρ 0 3,0 2,0 ρ 1 ρ 0 0, 0, Figue 5 Coefficient of elative engine owe euied in tun fo T-55 Figue 6 Efficiency coefficient of tuning mechanism fo T-55

5 5 y ρ 0 h ρ 2 ρ ρ 3 3 ρ 1 2 ρ 1 ρ 2 ρ 0 0, 1 ρ 3 ρ Figue 7 Coefficient of elative engine owe euied in tun fo VP-80 Figue 8 Efficiency coefficient of tuning mechanism fo VP-80 6 y m z 5 ρ 0 h m z 3 2 ρ 7 ρ 1 ρ 7 ρ 1 1 ρ 3 0, ρ Figue 9 Coefficient of elative engine owe euied in tun fo -8 Figue 10 Efficiency coefficient of tuning mechanism fo -8 Analysis of the obtained esults shows that: the incease of elative fixed kinematic tuning adius affects the decease of the coefficient of elative engine owe euied in tun with incease in the efficiency coefficient of the tuning mechanism η fo elative tuning adii ρ which ae geate than the elative fixed kinematic tuning adius ρ i fo single tansmission levels, the decease of coefficient and incease of coefficient η is esecially onounced in the inteval of elative fixed kinematic tuning adius ρ i { 1.0; 5.0}, fo intevals of elative fixed kinematic tuning adius ρ i { 5.1; 15.0} the tend of favouable values of coefficients is moe modeate, 5

6 the existence of seveal elative fixed kinematic tuning adii that ae diffeent in magnitude, allows tansitioning of the tun by the tacked vehicle fom a highe level ( ρ ) to the neaest lowe level ( ρ i 1) fo the case when tun needs to be efomed with elative adius smalle than ρ i, and geate than ρ 0 = 0.5, tansitioning of the tun made by a tacked vehicle fom a highe level ( ρ i ) to the neaest lowe level ( ρ i 1 ) in case when tun needs to be efomed with a elative adius smalle than ρ i, and geate than ρ 0 = 0.5, deceases the engine load and the load on fiction elements of the tuning mechanism.. Conclusion The decease in tuning adius duing the tun of a tacked vehicle leads to inceased tuning esistances and inceased load on the engine and tansmission devices of the vehicle. ajo incease in the engine load esults in tun with elative adii ρ 30, and esecially with elative adii ρ 15. The existing oblem can be ovecome by designing the tuning mechanism which aat fom the minimal elative fixed kinematic tuning adius ρ 0 = 0.5 has one o moe elative fixed kinematic tuning adii ρ i The existence of the elative fixed kinematic tuning adius geate than ρ 0 = 0.5 esults in decease of the engine load and tansmission elements fo the case of tuns with tuning adii eual o geate than the elative fixed kinematic tuning adius. The coefficients of elative engine owe euied in a tun as well as efficiency coefficients of the tuning mechanism η have favouable values fo those tuning adii. Favouable tend of the values of coefficients elative fixed kinematic tuning adii in the inteval fixed kinematic tuning adius is esecially onounced fo the ρ { 1.0; 5.0}. In the intevals of elative i ρ i { 5.1; 15.0} the tend of favouable values of coefficients is of moe modeate intensity. In the ange of tuns with elative fixed kinematic tuning adii geate than ρ i = 15, coefficients do not change significantly. When designing new tansmissions of tacked vehicles, it is desiable to ealise one elative fixed kinematic tuning adius ρ 0 = 0.5 and seveal elative fixed kinematic tuning adii in the inteval ρ i { 1.0; 15.0}. efeences [1] Faobin, J. E.: Teoia ovoota tansotnih mašin, ašinostoenie, Leningad, 1970 [2] Kasnenkov V. I., Vašec, A. D.: Poektiovanie lanetanih mehanizmov tansotnih mašin, ašinostoenie, oskva, 1986 [3] Nosov, N. A.,...: asčet i konstuiovanie guseničnih mašin, ašinostoenie, Leningad, 1972 [] Zabavnikov, N. A.: Osnovi teoii tansotnih guseničnih mašin, ašinostoenie, oscow, 1975 [5] ***, obeno vozilo ešadije VP -80A, TU-I, SSNO, eogad, 1989 [6] ***, Tenk T-3, TU-I, SSNO, eogad, 1966 [7] ***, Tenk T-55, TU-I, SSNO, eogad, 1966 [8] ***, Tenk -8A, TU-I, SSNO, eogad, 1988 Vjekoslav Stojković, OH- Institut za obambene studije, istaživanja i azvoj, ijenička cesta 6, Zageb, Coatia, vstojkovic@moh.h Enest azijanac, Fakultet ometnih znanosti, Vukelićeva, Zageb, Coatia, baza@fz.h iko Jakočić, GS OS H Hvatsko vojno učilište Peta Zinski, Ilica 256b, Zageb, Coatia, mjakoc@yahoo.com i 6

Chapter 5 Force and Motion

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