Reserch Paper On Taper Leaf Spring

Development on the forming principle and control  model of taper leaf spring 

Liu Junying, Li Suling, Gao Lei  School of mechanical engineering, Shandong university of technology, 255091, Zibo City, China  , ljy58@163.com

Taper leaf spring mill is the special equipment  for rolling leaf springs used in automobiles. During the  rolling technological process of taper leaf spring, in order to obtain the equal-stress mechanics characteristic of taper leaf spring it is  need to control the dynamic  changes of gap between rollers, completing the figure of  parabola or other special ones along the longitudinal  parabola of un-machined plates. Therefore, the type of  two-degree computer controlling system is adopted in  the controlling system of taper leaf spring mill, in which, the top one is industrial computer, the below one is PLC.  Structure characteristics  and composing principles  based on the dynamic controlling system are researched, establishing the mathematics model of controlling system. The controlling program is developed based on the manufacturing craftwork flow of taper leaf spring. The equipment has been applied in the practical manufacturing, achieving kinds of equal-stress taper leaf  spring provided with different parabola coefficients. 

Usually, increasing the proportional coefficient P K   could fasten the response, which is good for reducing static  difference. But, if the proportional coefficient is too big, it will bring overshoot and surge to the system, breaking the stability. Increasing the integrating constant T is good for reducing overshoot and surge, which will make the system more stable, but could slow down the speed of static difference eliminating. Increasing the differential time D T  is in favor of fastening the response of system, reducing overshoot, advancing stability, but, is liable to reducing the  ability of resisting to disturbing especially for the sensitive  response to disturbance. Considering the above influence caused by parameters, first, all the parameters should become proportional, then integrated, differential in the end. 

What is introduced is the electro-hydraulic servo  control system composing computer as host computer and  PLC as lower computer, which has been applied in taper leaf  spring mill which could manufacture all kinds of taper leaf  springs used in cars in China. The developed completely  automatic hydraulic taper leaf spring mill based on the PLC dynamic controlling as lower computer is simple in structure，low in cost，high in producing efficiency，stable in working，simple in maintaining and convenient in adjusting, especially easy in modifying PLC parameters through host computer, which is able to roll flat springs of  different kinds of types ， sections and length, high  lightening the efficiency of mill. Besides, according to the request of market, it is needed to install special accessories  to complete special adjusting, which could satisfy the  requirement of flat springs with special structure, high  lightening the applicability of mill and satisfying diverse  requirements.

Submitted By
Rupesh Kumar Chauhan
Roll no 79
PGDIE 42