Spring suspension system, in particular for a machine

Abstract

1. Spring suspension system, in particular for a machine. 2. The invention relates to a spring suspension system, in particular for a machine such as a tractor or the like, with a spring suspension cylinder ( 10 ) to which varying load pressures (m) are applied, the piston ( 12 ) and rod ( 14 ) sides of which suspension cylinder may each be connected to a suspension reservoir ( 16, 18 ) by way of a locking device ( 20 ) which blocks the spring suspension and with an equalization device ( 28 ) which effects equalization of the pressure of the system to the currently prevailing load pressure (m) prior to activation of the spring suspension. Consequently, with the spring suspension system claimed for the invention pressure equalization may be effected between the spring suspension cylinder and the suspension reservoir and in this way uncontrolled movement of the axle when the suspension system is activated may be prevented.

1 . A spring suspension system, for a machine such as a tractor or the like, with a suspension cylinder ( 10 ) to which different load pressures (m) may be applied, the piston ( 12 ) and rod ( 14 ) sides of which may each be connected to a suspension reservoir ( 16 ,  18 ) by way of a locking device ( 20 ) which blocks the spring suspension, and with an equalization device ( 28 ) which effects equalization of the pressure of the system to currently prevailing load pressure (m).  
     
     
         2 . A spring suspension system as specified in  claim 1 , wherein the suspension reservoirs ( 16 ,  18 ) and the locking device ( 20 ) are connected to a supply device ( 30 ) as part of the equalization device ( 28 ), which provides connection optionally to a pressure supply source (P) and/or to a tank connection (T) by means of a switching device ( 32 ).  
     
     
         3 . A spring suspension system as specified in  claim 2 , wherein the suspension reservoirs ( 16 ,  18 ) may be separated from the supply device ( 30 ) each by way of a return valve ( 34 ,  36 ) which is held spring loaded in its closed position and which assumes its opened position in the direction of the pertinent suspension reservoir ( 16 ,  18 ).  
     
     
         4 . A spring suspension system as specified in  claim 3 , wherein an overload monitoring device (LS) which activates the pressure supply source (P), in particular in the form of a hydropump, is connected to a branch ( 38 ) to the line ( 40 ) with the locking device ( 26 ) and with which may be associated the suspension reservoir ( 16 ) with return valve ( 43 ) for the piston side ( 12 ) of the suspension cylinder ( 10 ), so that such pressure supply source (P) delivers the system pressure required.  
     
     
         5 . A spring suspension system as specified in  claim 4 , wherein the suspension reservoir ( 16 ) is connected to the line ( 40 ) by the return valve ( 34 ).  
     
     
         6 . A spring suspension system as specified in one of  claims 1  to  5 , wherein the locking device ( 20 ) has for both the piston side ( 12 ) and for the rod side ( 14 ) of the suspension cylinder ( 18 ) a 2/2-way pilot valve ( 44 ,  46 ) which when in its unactuated base position blocks the fluid conducting path to the associated suspension reservoir ( 16 ) and frees such path in the opposite direction.  
     
     
         7 . A spring suspension system as specified in one of  claims 1  to  6 , wherein the equalization device ( 28 ) has for both the piston side ( 12 ) and for the rod side ( 14 ) of the suspension cylinder ( 10 ), inside the supply device ( 30 ), 3/2-way pilot valves ( 48 ,  50 ) which when in their unactuated base position are connected to the tank connection (T) and on their inlet side are connected to each other so as to conduct fluid.  
     
     
         8 . A spring suspension system as specified in  claim 7 , wherein an opening control line ( 41 ) for a releasable return valve ( 43 ) is connected to a line ( 45 ) between the return valve ( 36 ) and the 3/2-way valve ( 50 ).  
     
     
         9 . A spring suspension system as specified in  claim 7  or  8 , wherein the suspension cylinder ( 10 ), in particular the position of the piston rod ( 24 ), is monitored by a sensor device which transmits to a data interpretation unit its signals, which activate the pilot valves ( 44 ,  46 ,  48 ,  50 ) for a switching process.