Method and drive system for the control/regulation of linear pressure/cast movement

Abstract

The invention relates to a method for controlled driving of the cast axle ( 8 ) of pressure die casting machines, comprising a drive piston ( 15 ), wherein the forward and return motion of the piston ( 15 ) is carried out in a controlled manner. The invention is characterized in that the oil flow or oil pressure on the piston rod side is controlled/regulated by a pump ( 30 ) and additionally by a throttle valve ( 103 ) working in parallel at least during the filling phase, especially during the fast forward motion part.

1 . A method for controlling/regulating the linear pressing/casting movement by means of a driving piston on injection molding machines and compression molding machines and presses, whereby a hydraulic medium is used at least on the working side and/or the piston rod side, 
 characterized in that 
 the pressing/casting movement is controllable/regulatable with respect to an oil flow and/or an oil pressure on the piston rod side by means of a pump ( 30 ) and at least in phases additionally through a throttle valve ( 34 ,  46 ) that operates in parallel with the pump ( 30 ).  
   
     
     
         2 . The method according to  claim 1 , 
 characterized in that 
 the piston is driven for the forward movement by the gas pressure, in particular nitrogen (N 2 ) from a nitrogen container through appropriate valves.  
   
     
     
         3 . The method according to  claim 2 , 
 characterized in that 
 the driving piston is operated on both sides with a hydraulic medium and the forward movement is operated by a piston-type accumulator.  
   
     
     
         4 . The method according to one of claims  1  through  3 , 
 characterized in that 
 the pump ( 30 ) is designed as a fixed-volume pump and the controlling/regulating of both the pump ( 30 ) and the throttle valve is accomplished by a servo motor ( 104 ,  105 ).  
 
 
     
     
         5 . The method according to one of claims  1  through  4 , 
 characterized in that 
 both the pump ( 30 ) and the throttle return flow are connected to an oil container ( 110 ), preferably closed by a film covering, and vacuum degassed oil is used.  
 
 
     
     
         6 . The method according to one of claims  1  through  5 , 
 characterized in that 
 in the hot chamber method, the rapid shot is controllable/regulatable with a pump ( 30 ) and throttle valve ( 34 ,  46 ), and in injection molding the rapid injection is similarly controllable/regulatable.  
 
 
     
     
         7 . The method according to one of claims  1  through  6 , 
 characterized in that 
 in the case of maximum oil flow through the pump and throttle valve according to 100%, the pump ( 30 ) is designed for 10% to 50%, preferably 15% to 30% of this oil flow.  
 
 
     
     
         8 . A drive system for controlling/regulating a driving piston for the pressing/casting movement in injection molding machines and compression molding machines or presses, whereby a hydraulic medium is provided at least on the working side and/or the piston rod side, 
 characterized in that 
 both a pump ( 30 ) and in addition at least one throttle ( 103 ) connected in parallel are provided on the piston rod side such that both the flow through the pump ( 30 ) and the flow through the throttle ( 103 ) are controllable/regulatable by motor means at least for the range of the rapid forward movement.  
   
     
     
         9 . The drive system according to  claim 8 , 
 characterized in that 
 the driving piston ( 15 ) has a gas impingement with a direct connection to a pressurized nitrogen container on the back side ( 14 ) (for the forward movement).  
   
     
     
         10 . The drive system according to  claim 8  or  9 , 
 characterized in that 
 the pump ( 30 ) is designed as a fixed-volume pump with a servo motor drive ( 104 ,  105 ).  
 
 
     
     
         11 . The drive system according to one of claims  8  through  10 , 
 characterized in that 
 the throttle ( 103 ) has a motor positioning drive, in particular a servo motor ( 104 ,  105 ), the overdrive being accomplished by a transmission, a spindle or a crank drive.  
 
 
     
     
         12 . The drive system according to  claim 11 , 
 characterized in that 
 the positioning drive has a spindle overdrive with a spindle nut whereby the spindle nut is installed in the servo valve, and the servo motor ( 104 ,  105 ), the spindle and throttle ( 103 ) form one structural unit.  
   
     
     
         13 . The drive system according to  claim 12 , 
 characterized in that 
 the throttle ( 103 ) is designed as a piston valve, and the throttle cross-section is adjustable directly by way of the servo motor ( 104 ,  105 ) and the spindle overdrive through a linear displacement.  
   
     
     
         14 . The drive system according to one of claims  8  through  13 , 
 characterized in that 
 it has pressure gauges for measuring the injection force and a distance measuring system for the position of the casting piston.  
 
 
     
     
         15 . The drive system according to one of claims  8  through  14 , 
 characterized in that 
 it has a control/regulating unit which is designed as a multi-axial and/or multi-variable regulating unit whereby the position and/or the speed and/or the force of the driving piston ( 15 ) is/are detectable in particular.