Dual leaf suspension for vehicle drive arrangement

Abstract

A vehicle drive arrangement for a vehicle of the type having differential power transmission arrangement that converts the rotatory motion of the rotatory power shaft to rotatory motion of first and second drive shafts disposed substantially orthogonal the rotatory power shaft. Primary leaf springs are each coupled at their respective centers to respective drive shafts by pivotal arrangements. The first and second primary springs may include helical springs that are used in place of, or in combination with, the primary leaf springs. Secondary leaf springs may be splayed and therefore need not be arranged parallel to the primary leaf springs. Control over vehicle kinematics is enhanced by configuring the resilience of a fulcrum bumper using resilient, rheological, or active systems. An active system will control vehicle height while stationary to facilitate loading and unloading of the vehicle.

It is claimed: 
     
         1 . A vehicle drive arrangement for a vehicle of the type having a chassis extending longitudinally, and a rotatory power shaft extending longitudinally along the chassis, the rotatory power shaft being coupled at a rearward end thereof to a differential arrangement for converting the rotatory motion of the rotatory power shaft rotatory motion of first and second drive shafts have a respective longitudinal axis, the vehicle drive arrangement comprising:
 a differential coupling arrangement for fixedly coupling the differential arrangement to the chassis;   first and second universal coupling arrangement for coupling respective ones of the first and second drive shafts to the differential arrangement, whereby the first and second drive shafts are transaxially displaceable;   first and second spring elements coupled to respective ones of the first and second drive shafts at respective ends distal from said first and second universal coupling arrangements, and to the chassis;   first and second secondary leaf springs coupled at respective first ends thereof to the first and second drive shafts at respective ends distal from said first and second universal coupling arrangements, and at respective second ends thereof to the chassis; and   a beam having first and second ends, said beam being coupled at the first and second ends to respective ones of the first and second drive shafts at respective ends distal from said first and second universal coupling arrangements, said first and second spring elements are respective first and second primary leaf springs each coupled at respective first ends thereof to the chassis and at substantially the center thereof to respective ones of the first and second drive shafts, said first and second secondary leaf springs are disposed above said respective first and second primary leaf springs.   
     
     
         2 . The vehicle drive arrangement of  claim 1 , wherein said first and second secondary leaf springs are arranged to extend through the chassis. 
     
     
         3 . The vehicle drive arrangement of  claim 1 , wherein said first and second secondary leaf springs are arranged to be substantially parallel to said respective first and second primary leaf springs. 
     
     
         4 . A vehicle suspension arrangement for a vehicle having a chassis and a drive axle, the vehicle suspension to the chassis of the vehicle;
 a secondary leaf spring having a substantially longitudinal configuration, a first end for coupling to the chassis, and a second end;   a coupling element for coupling to the drive axle;   a first pivot joint for pivotally coupling to substantially the center of said primary leaf spring intermediate of its first and second ends for coupling to said coupling element; and   a second pivot joint for pivotally coupling the second end of said secondary leaf spring to said coupling element.   
     
     
         5 . The vehicle suspension arrangement of  claim 4 , wherein there is further provided a primary leaf coupler for securing said first pivot joint to substantially the center of said primary leaf spring. 
     
     
         6 . The vehicle suspension arrangement of  claim 5 , wherein said first pivot joint is formed of first and second pivot portions, said first pivot portion being fixedly coupled to said primary leaf coupler, and said second pivot portion being fixedly coupled to said coupling element, said first and second pivot portion being configured to be pivotally coupled to each other. 
     
     
         7 . The vehicle suspension arrangement of  claim 5 , wherein said first pivot joint is configured to enable limited pivotal motion between said primary leaf spring and said coupled element, the pivotal motion being directed longitudinally in see-saw like relation to said primary leaf spring. 
     
     
         8 . A vehicle suspension arrangement for a vehicle having a chassis and a drive axle, the vehicle suspension arrangement comprising:
 a primary spring having a substantially helical configuration, said primary spring having a first end for coupling to the chassis of the vehicle, and a second end for coupling to an axle of the vehicle;   a secondary leaf spring having a substantially longitudinal configuration, said secondary leaf spring having a first end for coupling to the chassis, and a second end; and   a coupling element for coupling the second ends of said secondary leaf spring to the drive axle.   
     
     
         9 . The vehicle suspension arrangement of  claim 8 , wherein said coupling element comprises a pivot joint for pivotally coupling the second end of said secondary leaf spring to the drive axle. 
     
     
         10 . The vehicle suspension arrangement of  claim 8 , wherein there is provided a further primary spring having respective first and second ends thereof coupled to the chassis, and being coupled at substantially the center thereof to the drive shaft and to the second end of said primary spring. 
     
     
         11 . The vehicle suspension arrangement of  claim 10 , wherein said further primary spring comprises a flat locating plate. 
     
     
         12 . The vehicle suspension of  claim 11 , wherein said further primary spring comprises single plate main leaf spring. 
     
     
         13 . A vehicle suspension arrangement comprising:
 a primary leaf spring having a plan view longitudinal configuration and first and second ends for coupling to the chassis of the vehicle;   a secondary leaf spring having a plan view longitudinal configuration, a first end for coupling to the chassis, and a second end;   wherein the plan view longitudinal configuration of said secondary leaf spring is arranged to be angularly displaced with respect to the plan view longitudinal configuration of said primary leaf spring.   
     
     
         14 . The vehicle suspension arrangement of  claim 13 , wherein the plan view longitudinal configuration of said secondary leaf spring and the plan view longitudinal configuration of said primary leaf spring are angularly displaced with respect to each other by an angle of approximately between  5  to  10 . 
     
     
         15 . The vehicle suspension arrangement of  claim 14 , wherein the plan view longitudinal configuration of said primary leaf spring is arranged substantially parallel to a chassis frame rail of the vehicle.