Take the analysis getting power of transmission and athletic character

718) ; The coefficient of friction between belt of – of F – – and flange; Drive of – of A – – takes the bag part on belt annulus (Rad) . The Ou La that type chafes for withy body namely on is formulary. (7-5) the derivation of type: Below in order to make the same score model head the tight side tension when be a research area to be about to skid on driving pulley and the concern between the pulling force side the pine. Hypothesis belt does not have flexibility in the job stretchy, and oversight bends, the influence of the quality of centrifugal force and belt. If pursue,7 – are shown 9 times, take one small paragraph of transmission belt Dl, express to take wheel pair with DN this are small of paragraph of transmission belt pressure. Small the pulling force that heads one aspect of the matter is paragraph of drive F, the pulling force of another end is F ＋ DF, attrition force is F · DN, f is taken for transmission with the coefficient of friction between belt annulus (take to V, with Fv of equivalent coefficient of friction, , f is belt annulus annulus groovy horn) . Criterion because Da is very small, so Sin(da/2)»da/2, and skip 2 rank minim DFsin(da/2) , get DN=Fda to take Cos(da/2)»1 again, get FdN=dF or, can be gotten then or integral of DF/F=fda both sides is gotten namely if similar ground thinks, the total length when transmission belt is working is changeless, criterion the addition of its tight side tension measures the decrement that should be equal to loose edge pulling force, namely or (7 – 6) type (7 – 4) era enters type (7 – 6) (7 – 7) type (7 – 7) era enters type (7 – 5) after arranging, attainable belt the greatest effective and circumferential power that transmission can transfer (7 – 8) by type (7 – 8) knowable, take drive the greatest effective and circumferential power and F0, A and belt and take round of material to wait for an element to concern character. F0, A, F more big, the greatest effective and circumferential power also heals big. Among them the impact of F0 is the biggest, affect the working ability that takes drive directly, but if F0 is too big, will make the service life of the belt shortens. When taking transmission to design so must value of reasonable and affirmatory F0. 2, the flexibility that takes drive slides and skid taking is elastomer, flexibility can arise below tensile action stretchy, stretch and stretchy quantity follows tensile increase and decrease and increase and decrease. Take transmission to be in working process, strict limit and the pulling force by the side of the pine differ. Should take in A the dot is circled on when driving pulley (see a picture 7 – 10) , the circumferential speed V1 of the speed V of the belt and driving pulley is equal. But in taking the course that turns to B dot from A dot, what suffer pulling force to fall gradually by F1 F2, stretch and stretchy quantity also wants to be reduced accordingly. Such belts are one side on driving pulley annulus of going along with is ongoing, contract backward at the same time, the rate that carries accordingly the circumferential speed under driving pulley, cause both between happen to slide relatively. On driven pulley, circumstance as it happens is contrary, the speed V that takes namely is more than the circumferential speed V2 of driven pulley, both between also happen to slide relatively. The belt that the flexibility that because take,this plants is out of shape and causes and belt annulus between slip, call flexibility to slide. Flexibility slides is a kind of when in taking drive, cannot avoid normal physics phenomenon. As a result of stretch and slip existence, make belt chafe with the generation between belt annulus and wear away; The circumferential speed V2 of driven pulley the circumferential speed V1 under driving pulley, produced speed loss namely. Loss of this kind of speed returns the load outside following change and change, this makes belt transmission is unwarrantable accurate drive is compared. Show speed losing rate with sliding ratio E normally, namely (7 – 9) 1~2% of general E ＝ , in the consideration stretch and slip circumstance falls, the drive that takes drive is compared for (7 – 10) – of – of – of the N1 in type, N2 is given priority to respectively, the rotate speed of driven pulley (R/min) ; – of – of – of D1, D2 is given priority to respectively, the datum diameter of driven pulley (Mm) . Say commonly, not be to contact arc to go up to produce flexibility to slide entirely. Osculatory arc cent slides relatively to have (slip arc) and without relatively slip (Jing Hu) two parts, the central part of their place correspondence, call slip part respectively (A¢ ) with static horn (A² ) . Carry out a proof, jing Hu always happens in belt enter belt annulus this at the same time (see a picture 7 – 10) . When taking transmission not to deliver load, slip horn is 0, as the addition of load, slip contend is increased gradually and static contend is reduced gradually, be equal to packet of horn to slip horn and static horn is zero hour, namely stretch and slip when enlarging whole contact arc, the effective and circumferential power that takes drive reachs maximum, if load goes further,increase, be taken and will happen between belt annulus skid. Should take transmission to appear when skidding, cannot work normally, transmission invalidation. Take transmission to should avoid to appear in regular job so skid, the circumferential power that needs to deliver namely cannot be more than Fmax of the greatest effective and circumferential power. 3, the area of stress analysis drive that transmission takes is in working process, can produce 3 kinds of stress (one) strict limit pulls stress S1 and loose edge to pull F1/A of ＝ of stress S2 S1 (MPa) S2=F2/A (MPa) strict limit of – of – of – of the F1 in type, F2, loose edge is tensile (N) ; The cut area that – of A – – takes (Mm2) . (2) curve stress Sb belt to be in bypass when belt annulus, curve stress because of bend and arising (see a picture 7 – 11) . It is with V belt exemple, criterion by material mechanical and knowable curve stress to be and M ＝ EI/r, w ＝ I/y0, r ＝ D/2, so (MPa) (7 – 11) the stretch model that strip of – of – of – of the E in type expects is measured (MPa) ; The neutral line with sectional belt of drive of – of Y0 – – comes the outerest space (Mm) ; – of D – – takes round of datum diameter (Mm) ; Radius of curvature of neutral line of – of R – – (Mm) ; – of I – – is inertial be apart from (Mm4) . By type (7 – 11) knowable, take more thick, belt annulus diameter heals small, in be being taken curve stress to heal big. Accordingly, belt circle in zonule annulus when going up curve stress Sb1 to be more than circle in large area annulus when going up curve stress Sb2. Curve stress greatly to had avoided, when design V takes drive, answer V the Dmin of the smallest datum diameter of belt annulus tries to restrict (express 7 – 3) . Express 7-3 V the smallest datum diameter of belt annulus and the quality V that V takes every meters to grow take model YZABCDEdmin(mm)205075125200355500q(kg/m)0.

020.

060.

100.

170.

300.

620.

90 (3) centrifugal pull stress Sc belt to be in bypass circular motion is made when belt annulus, produce centrifugal power thereby, cause in the belt centrifugal pull stress Sc. If pursue,7 – are shown 12 times, set the speed of the belt to be V(m/s) , take small paragraph take Dl (M) , small paragraph of centrifugal force on the belt for C, criterion the quality with every meters chief belt of drive of – of – of – of – of the Q in type (Kg/m) . See a table 7 – 3. The pulling force that in setting centrifugal force to be taken in transmission, causes is Fc, take small paragraph of belt Dl is separate system, because Da is very small,can get according to balancing a condition, desirable Sin(da/2)»da/2, get Fc=qv2 (N) (7 – 12) accordingly, in the belt centrifugal pull stress Sc to be (MPa) (7 – 13) the cut area that drive of – of – of – of the A in type takes (Mm2) . By type (7 – 13) knowable, the speed of the belt is right centrifugal pull stress the impact is very big. Although centrifugal force produces the arc that taking circular motion only paragraph go up, but from this and those who cause is centrifugal pull stress however what action takes at transmission is full-length on, and everywhere size is equal. From the existence of mental efforts, make transmission takes what go up with belt annulus interface pressure is reduced, the working ability that takes drive will be reduced somewhat. By afore-mentioned analysises knowable, take drive when transferring power, the generation in the belt pulls stress, bend stress and centrifugal pull stress, if pursue,its stress distributings 7 – are shown 13 times. Can see from inside the graph, the stress that enters area of driving pulley place in strict limit is the greatest, its value is (7 – 14) if pursue,7 – are shown 13 times, knowable, take when moving, action is taking some stress of the dot, it is to follow it located the position differs and change, be being taken so is to changing of the job below stress, when stress circular time reachs fair numerical value hind, belt general produces exhaustion to destroy. The stress that graph 7-13 takes distributings CNC Milling CNC Machining