Fan shroud and radiator fan for a motor vehicle, and radiator fan having the fan shroud

Abstract

A fan shroud for a radiator fan contains a central impeller receptacle for receiving a radiator impeller, which receptacle defines a rotational axis for the radiator impeller which axis is oriented in an axial direction. The axial direction extends from an inflow side to a pressure side of the fan shroud. A shroud ring is provided, wherein a fan plane perpendicular to the axial direction is defined by the impeller receptacle and the shroud ring. A plurality of struts extend from the impeller receptacle to the shroud ring and extend from the inflow side to the pressure side. With a strut base, the struts are fastened to the impeller receptacle, and, with a strut tip, are fastened to the shroud ring. The struts are oriented at a strut angle in relation to the fan plane which angle varies from the strut base to the strut tip.

1 . A fan shroud for a radiator fan of a motor vehicle, the fan shroud comprising:
 a central impeller receptacle for receiving a fan impeller, said central impeller receptacle defining a rotational axis for the fan impeller, the rotational axis being oriented in an axial direction, the axial direction extending from an inflow side to a pressure side of the fan shroud;   a shroud ring, wherein a fan plane perpendicular to the axial direction is defined by said central impeller receptacle and said shroud ring; and   a plurality of struts each having a strut base and a strut tip, said struts extending from said central impeller receptacle as far as said shroud ring and also extending from the inflow side to the pressure side and said struts being fastened at said strut base to said central impeller receptacle and at said strut tip to said shroud ring, wherein said struts are oriented with respect to the fan plane at a strut angle which changes from said strut base to said strut tip, the strut angle changes differently in an inner region starting from said strut base in comparison to an outer region which extends as far as said strut tip.   
     
     
         2 . The fan shroud according to  claim 1 , wherein a relative change in the strut angle is smaller at least in terms of value in said inner region than in said outer region. 
     
     
         3 . The fan shroud according to  claim 1 , wherein the strut angle initially increases in said inner region and subsequently decreases again in said outer region. 
     
     
         4 . The fan shroud according to  claim 1 , wherein said struts each have an overall length between said strut base and said strut tip, and said inner region extends over 60% to 90% of the overall length. 
     
     
         5 . The fan shroud according to  claim 1 , wherein a change in the strut angle in at least one of said inner and outer regions is constant. 
     
     
         6 . The fan shroud according to  claim 1 , wherein the strut angle is greater at said strut base than at said strut tip. 
     
     
         7 . The fan shroud according to  claim 1 , wherein said inner region extends over 60% to 90% of an overall length of said strut and is adjoined by said outer region which extends as far as said strut tip, and in that the strut angle increases continuously starting from said strut base in said inner region up to a maximum value and subsequently decreases continuously in said outer region as far as said strut tip to a minimum value which is smaller than the strut angle at said strut base. 
     
     
         8 . The fan shroud according to  claim 1 , wherein the strut angle at said strut base lies in a range of 35° to 55°. 
     
     
         9 . The fan shroud according to  claim 1 , wherein the strut angle increases in said inner region up to a maximum strut angle in a range of 55° to 80°. 
     
     
         10 . The fan shroud according to  claim 1 , wherein the strut angle at said strut tip lies in a range of 25° to 45°. 
     
     
         11 . The fan shroud according to  claim 1 , wherein the strut angle changes in said inner region by 10° to 30° and/or in said outer region by 20° to 50°. 
     
     
         12 . The fan shroud according to  claim 1 , wherein said struts each have an overall length between said strut base and said strut tip, and said inner region extends over 70% to 85% of the overall length. 
     
     
         13 . The fan shroud according to  claim 1 , wherein a change in the strut angle in both said inner region and said outer region is constant. 
     
     
         14 . The fan shroud according to  claim 1 , wherein the strut angle at said strut base lies in a range of 40° to 50°. 
     
     
         15 . The fan shroud according to  claim 1 , wherein the strut angle increases in said inner region up to a maximum strut angle in a range of 65° to 75°. 
     
     
         16 . The fan shroud according to  claim 1 , wherein the strut angle at said strut tip lies in a range of 30° to 40°. 
     
     
         17 . The fan shroud according to  claim 1 , wherein the strut angle changes in said inner region by 15° to 25° and/or in said outer region by 30° to 40°. 
     
     
         18 . A radiator fan for a motor vehicle, the radiator fan comprising:
 said fan shroud according to  claim 1 ; and   a fan impeller fastened to said fan shroud and said fan impeller being rotatable about a rotational axis.