Exhaust Gas Heat Exchanger, Especially for Motor Vehicles

Abstract

The invention relates to an exhaust gas heat exchanger ( 2 ), especially for motor vehicles, comprising a main flow path and a secondary flow path (bypass) for the exhaust gas. Said heat exchanger comprises a valve device ( 3 ) which is used to control the exhaust gas flow and can be actuated by a servomotor ( 4 ) by means of a transmission device ( 8, 6 ), the valve device ( 3 ) comprising a valve closing member fixed to a valve shaft (a). According to the invention, the valve shaft (a) can be loaded by a torsion spring ( 5 ) which can be supported on the valve shaft and on the valve device ( 3, 3 a ).

1 - 17 . (canceled)  
   
   
       18 . An exhaust gas heat exchanger ( 2 ), in particular for motor vehicles, with a main flow path and an alternate flow path (bypass) for the exhaust gas, with a valve mechanism ( 3 ) controlling an exhaust gas flow, operable by an actuator ( 4 ) via a transmission mechanism ( 8 ,  6 ), wherein valve mechanism ( 3 ) comprises a valve closing member ( 10 ) mounted on a valve shaft ( 9 ), characterized in that valve shaft ( 9 ) can be loaded by a torsion spring ( 5 ), which is braced on the one hand against valve mechanism ( 3 ,  3   a ) and against valve shaft ( 9 ) on the other.  
   
   
       19 . The exhaust gas heat exchanger according to  claim 18 , characterized in that the torsion spring is constructed as a helically wound spiral spring (leg spring  5 ) with two spring legs ( 5   a ,  5   b ) or as a spiral spring.  
   
   
       20 . The exhaust gas heat exchanger according to  claim 19 , characterized in that valve shaft ( 9 ) has a shaft section ( 9   b ) led out of valve mechanism ( 3 ,  3   a ), and that torsion spring ( 5 ) is arranged coaxially on shaft section ( 9   b ).  
   
   
       21 . The exhaust gas heat exchanger according to  claim 20 , characterized in that a bushing ( 11 ) is arranged inside torsion spring ( 5 ) on shaft section ( 9   b ).  
   
   
       22 . The exhaust gas heat exchanger according to  claim 21 , characterized in that a pivoted lever ( 6 ) that is articulated to a control rod ( 8 ) is fastened to an end ( 9   c ) of shaft section ( 9   b ).  
   
   
       23 . The exhaust gas heat exchanger according to  claim 22 , characterized in that the actuator is constructed as a negative pressure actuator ( 4 ).  
   
   
       24 . The exhaust gas heat exchanger according to  claim 23 , characterized in that torsion spring ( 5 ) is constructed as a reset spring for the negative pressure actuator ( 4 ).  
   
   
       25 . The exhaust gas heat exchanger according to  claim 24 , characterized in that actuator ( 4 ) is fastened to a housing ( 2   a ) of exhaust gas heat exchanger ( 2 ).  
   
   
       26 . The exhaust gas heat exchanger according to  claim 25 , characterized in that the valve closing member is constructed as a flap ( 10 ) and the valve shaft is constructed as a flap shaft ( 9 ).  
   
   
       27 . The exhaust gas heat exchanger according to  claim 26 , characterized in that flap shaft ( 9 ) is arranged centrically or off center with respect to flap ( 10 ).  
   
   
       28 . The exhaust gas valve according to  claim 18 , characterized in that valve shaft ( 9 ) has a shaft section ( 9   b ) led out of valve mechanism ( 3 ,  3   a ), and that torsion spring ( 5 ) is arranged coaxially on shaft section ( 9   b ).  
   
   
       29 . The exhaust gas valve according to  claim 18 , characterized in that the actuator is constructed as a negative pressure actuator ( 4 ).  
   
   
       30 . The exhaust gas valve according to  claim 18 , characterized in that torsion spring ( 5 ) is constructed as a reset spring for a negative pressure actuator ( 4 ).  
   
   
       31 . The exhaust gas valve according to  claim 18 , characterized in that the valve closing member is constructed as a flap ( 10 ) and the valve shaft is constructed as a flap shaft ( 9 ).  
   
   
       32 . An exhaust gas valve for an exhaust gas heat exchanger, in particular for motor vehicles, wherein exhaust gas valve ( 10 ) is pivotably seated on a flap shaft ( 9 ) that is in a housing ( 3   a ) and that is led out of housing ( 3   a ) and is operable by an actuator ( 4 ), characterized in that a torsion spring ( 5 ) biases flap shaft ( 9 ) in the pivoting direction and is arranged coaxially to flap shaft ( 9 ).  
   
   
       33 . The exhaust gas valve according to  claim 32 , characterized in that torsion spring ( 5 ) is arranged outside housing ( 3   a ) on flap shaft ( 9 ).  
   
   
       34 . The exhaust gas valve according to  claim 33 , characterized in that the torsion spring is constructed as a leg spring ( 5 ) with two spring legs ( 5   a ,  5   b ), which act in the circumferential direction on flap shaft ( 9 ) and are braced on housing ( 3   a ).  
   
   
       35 . The exhaust gas valve according to  claim 34 , characterized in that torsion spring ( 5 ) is constructed and arranged to be used as a reset spring for the actuator, said actuator being a pneumatic actuator ( 4 ).  
   
   
       36 . The exhaust gas valve according to  claim 35 , characterized in that at least one torsion spring ( 5 ) winds up when actuated.  
   
   
       37 . The exhaust gas valve according to  claim 35 , characterized in that at least one torsion spring ( 5 ) unwinds when actuated.  
   
   
       38 . The heat exchanger with a flap according to  claim 32.