Heat exchanger

Abstract

Refrigerant tubes each having a refrigerant side turning portion for changing a flow direction of refrigerant, and cooling medium tubes each having a cooling medium side turning portion for changing a flow direction of coolant for an electric motor MG for travelling are alternately stacked over each other between a refrigerant header tank and a cooling medium header tank. An outer fin is disposed in an outside air passage formed between the refrigerant tube and the coolant tube adjacent to each other. The refrigerant side turning portion is positioned closer to the cooling medium header tank than the refrigerant header tank. The cooling medium side turning portion is positioned closer to the refrigerant side header tank than the cooling medium header tank.

1 . A heat exchanger comprising:
 a first heat exchanging portion including a plurality of first tubes through which a first fluid flows, and a first tank extending in a direction of lamination of the first tubes to collect or distribute the first fluid flowing through the first tubes, the first heat exchanging portion being adapted to exchange heat between the first fluid and a third fluid flowing around the first tubes; and   a second heat exchanging portion including a plurality of second tubes through which a second fluid flows, and a second tank extending in a direction of lamination of the second tubes to collect or distribute the second fluid flowing through the second tubes, the second heat exchanging portion being adapted to exchange heat between the second fluid and the third fluid flowing around the second tubes, wherein   the first tubes and the second tubes are disposed between the first tank and the second tank,   at least one of the first tubes is disposed between the second tubes,   at least one of the second tubes is disposed between the first tubes,
 a space formed between the first tube and the second tube defines a third fluid passage through which the third fluid flows, 
 an outer fin is disposed in the third fluid passage, to promote heat exchange between both the heat exchanging portions while enabling heat transfer between the first fluid flowing through the first tubes and the second fluid flowing through the second tubes, 
 the first tube is provided with a first turning portion for changing a flow direction of the first fluid, 
 the second tube is provided with a second turning portion for changing a flow direction of the second fluid, 
 the first turning portion is positioned closer to the second tank than the first tank, and 
   the second turning portion is positioned closer to the first tank than the second tank.   
     
     
         2 . The heat exchanger according to  claim 1 , wherein
 a temperature of the first fluid introduced into the first heat exchanging portion is different from a temperature of the second fluid introduced into the second heat exchanging portion, and   the outer fin is disposed in a space formed between the first and second tubes adjacent to each other, between the adjacent first tubes, and between adjacent second tubes.   
     
     
         3 . The heat exchanger according to  claim 1 , wherein the first tube and the second tube are fixed to both the first tank and the second tank. 
     
     
         4 . The heat exchanger according to  claim 1 , wherein
 when one fluid with a higher temperature, of the first fluid introduced into the first heat exchanging portion and the second fluid introduced into the second heat exchanging portion is defined as a high-temperature side fluid, when an upstream side portion of a high-temperature side tube of the first tube and the second tube through which the high-temperature fluid flows with respect to a corresponding one of the first and second turning portions is defined as a high-temperature side tube upstream portion, and when a downstream side portion of the high-temperature side tube of the first tube and the second tube through which the high-temperature fluid flows with respect to the corresponding one of the first and second turning portions is defined as a high-temperature side tube downstream portion, the temperature of the third fluid is lower than that of the high-temperature side fluid, and the high-temperature side tube upstream portion of at least one of the high-temperature side tubes is positioned on an upstream side in a flow direction of the third fluid with respect to the high-temperature side tube downstream portion.   
     
     
         5 . The heat exchanger according to  claim 4 , wherein
 when one fluid having a lower temperature, of the first fluid introduced into the first heat exchanging portion and the second fluid introduced into the second heat exchanging portion is defined as a low-temperature side fluid, when an upstream side portion of a low-temperature side tube of the first tube and the second tube through which the low-temperature side fluid flows with respect to a corresponding one of the first and second turning portions is defined as a low-temperature side tube upstream portion, and when a downstream side portion of the low-temperature side tube of the first tube and the second tube through which the low-temperature fluid flows with respect to the corresponding one of the first and second turning portions is defined as a low-temperature side tube downstream portion, the temperature of the third fluid is lower than that of the low-temperature side fluid, and the low-temperature side tube upstream portion of at least one of the low-temperature side tubes is positioned on the upstream side in the flow direction of the third fluid with respect to the low-temperature side tube downstream portion.   
     
     
         6 . The heat exchanger according to  claim 1 , wherein the temperature of the third fluid is lower than that of one fluid having a higher temperature, of the first fluid introduced into the first heat exchanging portion and the second fluid introduced into the second heat exchanging portion, and is higher than that of the other fluid having a lower temperature. 
     
     
         7 . The heat exchanger according to  claim 1 , wherein
 when an upstream side portion of the first tube with respect to the first turning portion is defined as a first tube upstream portion, when a downstream side portion of the first tube with respect to the first turning portion is defined as a first tube downstream portion, when an upstream side portion of the second tube with respect to the second turning portion is defined as a second tube upstream portion, and when a downstream side portion of the second tube with respect to the second turning portion is defined as a second tube downstream portion, the first tube upstream portion and the second tube upstream portion are arranged in a direction of lamination of the first and second tubes, and the first tube downstream portion and the second tube downstream portion are arranged in the direction of lamination of the first and second tubes.   
     
     
         8 . The heat exchanger according to  claim 7 , wherein the first tube upstream portion and the second tube upstream portion are positioned on the upstream side in the flow direction of the third fluid with respect to the first tube downstream portion and the second tube downstream portion. 
     
     
         9 . The heat exchanger according to  claim 7 , wherein
 the first tubes include an upstream side first tube group in which the first fluid introduced into the first heat exchanging portion flows, and a downstream side first tube group in which the first fluid flowing from the upstream side first tube group flows to cause the first fluid to flow out the first heat exchanging portion,   the second tubes include an upstream side second tube group in which the second fluid introduced into the second heat exchanging portion flows, and a downstream side second tube group in which the second fluid flowing from the upstream side second tube group flows to cause the second fluid to flow out the second heat exchanging portion, and   the first tube upstream portion and the second tube upstream portion of the upstream side first tube group and the upstream side second tube group are positioned on the upstream side in the flow direction of the third fluid with respect to the first tube downstream portion and the second tube downstream portion.   
     
     
         10 . The heat exchanger according to  claim 9 , wherein
 the first tube upstream portion and the second tube upstream portion of the downstream side first tube group and the downstream side second tube group are positioned on the downstream side in the flow direction of the third fluid with respect to the first tube downstream portion and the second tube downstream portion.   
     
     
         11 . The heat exchanger according to  claim 1 , wherein the outer fin is coupled to the first and second tubes, and provided with a plurality of slits for locally weakening rigidity of the outer fin. 
     
     
         12 . The heat exchanger according to  claim 1 , wherein an area of a refrigerant passage of an intermediate part of at least one of the first turning portion and the second turning portion is larger than an area of a fluid passage of each of a fluid inflow portion and a fluid outflow portion of the one turning portion. 
     
     
         13 . The heat exchanger according to  claim 1 , further comprising
 an inner fin disposed within at least one of the first tube and the second tube, to promote the heat exchange between the first fluid or the second fluid, and the third fluid, wherein
 the inner fin has an end protruding into an internal space of the first turning portion or second turning portion. 
   
     
     
         14 . The heat exchanger according to  claim 1 , wherein each of the first tube and the second tube is made of a plate tube formed by bonding a pair of plates. 
     
     
         15 . The heat exchanger according to  claim 1 , wherein each of the first tube and the second tube is formed by bending a flat tube with a flat section in a direction perpendicular to the longitudinal direction of the tube.