Dual clutch transmission

Abstract

A dual clutch transmission, especially of a motor vehicle, includes a hydraulic circuit with a pump for delivering a hydraulic flow, a cooler for cooling the hydraulic flow, and a volume control valve for adjusting the hydraulic flow for a cooling system associated with two clutches of the dual clutch transmission. The volume control valve is constructed as a switching valve with at least two switching position ranges, supplying the hydraulic flow to a first cooling system associated with a first clutch in a first switching position range with a constant flow cross-section, and supplying the hydraulic flow to a second cooling system associated with a second clutch in a second switching position range with a constant flow cross-section, wherein the entire switching position range of the volume control valve is substantially formed by the first and second switching position ranges and only a narrow transition range therebetween.

1 - 9 . (canceled) 
     
     
         10 . A dual clutch transmission comprising two clutches and a hydraulic circuit, the hydraulic circuit comprising:
 at least one pump operative connected to a rotation-speed-controlled electric motor for conveying a hydraulic medium flow,   at least one cooler for cooling the hydraulic medium flow, and   a volume control valve for adjusting the hydraulic medium flow for a corresponding cooling system associated with each of the two clutches, wherein the volume control valve is constructed as a switching valve having at least two switching position ranges configured to convey the hydraulic medium flow in a first switching position range with a constant flow cross-section to a first cooling system associated with a first of the two clutches and to convey the hydraulic medium flow in a second switching position range with a constant flow cross-section to a second cooling system associated with a second of the two clutches, wherein a combined switching position range of the volume control valve is substantially formed by the at least two switching position ranges and by a narrow transition region located between adjacent switching position ranges of the at least two switching position ranges, wherein the narrow transition region is designed to be so narrow that a substantially constant flow cross-section results, and wherein a quantity of the hydraulic medium conveyed to at least one of the first and the second cooling system is adjusted by pulsed control of the volume control valve and by adjusting a rotation speed of the rotation-speed-controlled electric motor.   
     
     
         11 . The dual clutch transmission of  claim 10 , configured for installation in a motor vehicle. 
     
     
         12 . The dual clutch transmission of  claim 10 , wherein hydraulic circuit is configured for cooling the two clutches. 
     
     
         13 . The dual clutch transmission of  claim 10 , wherein the volume control valve is constructed as a 4/3-way switching valve or as a 3/2-way switching valve. 
     
     
         14 . The dual clutch transmission of  claim 10 , wherein the volume control valve is constructed as a 4/3-way switching valve and conveys the hydraulic medium flow in a third switching position range to a tank providing the hydraulic medium. 
     
     
         15 . The dual clutch transmission of  claim 10 , wherein the volume control valve is controlled electromagnetically or by an electric motor, or both. 
     
     
         16 . The dual clutch transmission of  claim 10 , further comprising an actuatable separation element interposed between the at least one pump and the rotation-speed-controlled electric motor. 
     
     
         17 . The dual clutch transmission of  claim 14 , wherein the second switching position range is located between the first switching position range and the third switching position range. 
     
     
         18 . The dual clutch transmission of  claim 14 , wherein the third switching position range is located between the first switching position range and the second switching position range.