tailieunhanh - The Motor Vehicle 2010 Part 17

Tham khảo tài liệu 'the motor vehicle 2010 part 17', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 1146 The Motor Vehicle Fig. Fig. will also be equal to P plus half the weight W of the axle and wheels. When a side force F acts on the body it sets up forces fl and f2 at the points of connection of the body and springs. The relative magnitudes of these forces and the exact positions at which they act will always be somewhat uncertain. However assuming them to be equal and to act as shown their resultant is a force F equal and opposite to F. These two forces F and F thus constitute a couple of magnitude Fh h being the perpendicular distance between them which unless the tilt is very large may be assumed to be equal to OG where O is the roll centre and if F is the centrifugal force G is the centre of gravity. For equilibrium there must be an equal and opposite couple to balance the couple Fh. This balancing couple is supplied by an increase q in the lefthand vertical reaction and a decrease of the same magnitude in the righthand one. Consequently the left-hand spring will sink a little lower than before while the right-hand one will rise by the same amount. The body will thus tilt about the point O on the roll axis. Similarly there will be a corresponding centre O at the rear so the line OO is the roll axis. The change q in the spring forces on each side will be equal to Fh t t being the spring base. The vertical forces between the wheels and the ground will change by amounts p where p FH T T being the wheel track and H the height of the line of action of the force F above the ground. If under the action of the side forces fiand f2 or more accurately under the reactions to those forces the springs deflect slightly sideways the point O would move sideways and therefore the centre of tilt would be slightly lower. Considering now the car with independent suspension as shown in Fig. the side force F again sets up a tilting couple and this has to be balanced by an increase p in the force exerted by the left-hand spring and an equal decrease in that .