Device for pressure regulation of hydraulic pumps

Abstract

Device for pressure regulation of a hydraulic pump for pumping a hydraulic medium under pressure, comprising delivery-quantity regulation; a piston unit including first biasing element; a piston member; a first surface on the piston member to be biased by a first biasing force of the hydraulic medium in a first direction; a second surface on the piston member engaged by the first biasing element to be biased by a second biasing force in a second direction, opposite to the first direction; second biasing element to bias the piston member in addition to the hydraulic medium and the first biasing element, thus influencing the pressure of the hydraulic medium.

1 - 9 . (canceled)  
   
   
       10 . A device for pressure regulation of a hydraulic pump for pumping a hydraulic medium under pressure, comprising delivery-quantity regulating means; 
 a piston unit including first biasing means;    a piston member;    a first surface on said piston member to be biased by a first biasing force of said hydraulic medium in a first direction;    a second surface on said piston member engaged by said first biasing means to be biased by a second biasing force in a second direction, opposite to said first direction;    second biasing means to bias said piston member in addition to said hydraulic medium and said first biasing means, thus influencing the pressure of said hydraulic medium.    
   
   
       11 . Device as claimed in  claim 10 , wherein said hydraulic medium is lubricating oil, and said hydraulic pump supplies said lubricating oil to an internal combustion engine.  
   
   
       12 . Device as claimed in  claim 10 , wherein said first biasing means comprise spring means.  
   
   
       13 . Device as claimed in  claim 10 , wherein said second biasing means comprise magnetic coil means and armature means acting onto said piston member.  
   
   
       14 . Device as claimed in  claim 10 , wherein said second biasing means comprise motor means for adjusting said second biasing force of said first biasing means.  
   
   
       15 . Device as claimed in  claim 14 , wherein said motor means comprise a stepping motor.  
   
   
       16 . Device as claimed in  claim 10 , further comprising a first path of hydraulic medium including means to provide an elevated pressure of hydraulic medium, and a second path of hydraulic medium including means to provide a lower pressure of said hydraulic medium as compared with said elevated pressure, and switch means for opening at least one of said paths.  
   
   
       17 . Device as claimed in  claim 16 , wherein said second biasing means comprise electric means to be supplied with electric current, the device further comprising means for urging said switch means to open said first path and to provide said elevated pressure when said supply of electric current fails.  
   
   
       18 . Device as claimed in  claim 10 , wherein said second biasing means comprise centrifugal valve means, drive means for rotating said centrifugal valve means to exert a speed-dependent influence onto the pressure of said lubricating oil.  
   
   
       19 . Device as claimed in  claim 18 , wherein said centrifugal valve means comprise 
 a first path for lubricating oil to said first surface of said piston member,    at least one second path for allowing partial draining of said lubricating oil,    switching piston means movable in an at least partially radial direction for alternatively opening one of said first and second paths, and    third biasing means for biasing said switching piston towards said first path.    
   
   
       20 . Device as claimed in  claim 19 , wherein said third biasing means comprise spring means.  
   
   
       21 . Device as claimed in  claim 19 , wherein said switching piston means are positioned inclined to said radial direction.  
   
   
       22 . Device as claimed in  claim 19 , wherein said drive means comprise shaft means and pumping gear means, said switching piston means and said third biasing means being located within said pumping gear means.  
   
   
       23 . Device as claimed in  claim 19 , wherein said switching piston means comprises projection means extending in said at least partially radial direction, said projection means being engaged by said third biasing means.  
   
   
       24 . Device as claimed in  claim 10 , wherein said second biasing means comprise electro-valve means.  
   
   
       25 . Device as claimed in  claim 10 , wherein said second biasing means comprise conveying means for said hydraulic medium for conveing it into a certain direction, thus altering the pressure of said hydraulic medium.  
   
   
       26 . Device as claimed in  claim 25 , wherein said conveying means comprise rotating shaft means and a helical groove in said shaft means.  
   
   
       27 . Device as claimed in  claim 10 , wherein said piston member comprises further at least a third surface to be biased by said hydraulic medium in said first direction, and switching means for allowing hydraulic medium to pass to at least one of said first and said at least third surfaces.  
   
   
       28 . Device as claimed in  claim 10 , further comprising hydraulic filter means arranged in series with said first surface of said piston member.  
   
   
       29 . Device as claimed in  claim 10 , further comprising housing means for receiving said hydraulic medium in at least one cavity, said second biasing means comprising at least one electrical component which is mounted outside said housing means and at least one hydraulic conduit means for communication of said cavity and said electrical component.  
   
   
       30 . Device as claimed in  claim 10 , further comprising housing means for receiving said piston member, said second biasing means comprising at least one electrical component attached to said housing means.