Fluid temperature adjustment device

Abstract

A fluid temperature adjustment device that includes a circulation flow path that circulates the cooling water in one direction between the engine and the radiator; a first flow path branched from the circulation flow path at a location downstream of the engine and upstream of the radiator; a second flow path branched from the circulation flow path at a location downstream of the radiator and upstream of the engine; a third flow path that communicates with a cooling water outlet of the heat exchanger and that is merged with the circulation flow path at a location downstream of the radiator and upstream of the engine; and a switching valve that selectively communicates between one of the first and second flow paths and a cooling water inlet of the heat exchanger.

1 . A fluid temperature adjustment device that includes a radiator that cools cooling water for an engine and a heat exchanger that exchanges heat between the cooling water and a working fluid for a transmission, the fluid temperature adjustment e device comprising:
 a circulation flow path that circulates the cooling water in one direction between the engine and the radiator;   a first flow path branched from the circulation flow path at a location downstream of the engine and upstream of the radiator;   a second flow path branched from the circulation flow path at a location downstream of the radiator and upstream of the engine;   a third flow path that communicates with a cooling water outlet of the heat exchanger and that is merged with the circulation flow path at a location downstream of the radiator and upstream of the engine; and   a switching valve that selectively communicates between one of the first and second flow paths and a cooling water inlet of the heat exchanger.   
     
     
         2 . The fluid temperature adjustment device according to  claim 1 , wherein
 the switching valve selectively communicates between one of the first and second flow paths and the cooling water inlet of the heat exchanger in accordance with a temperature of the working fluid.   
     
     
         3 . The fluid temperature adjustment device according to  claim 2 , wherein
 the third flow path is merged with the circulation flow path at a location downstream of a branched portion between the circulation flow path and the second flow path and upstream of the engine.   
     
     
         4 . The fluid temperature adjustment device according to  claim 3 , wherein
 the switching valve communicates between the first flow path and the cooling water inlet of the heat exchanger when the temperature of the working fluid is less than a first temperature, and communicates between the second flow path and the cooling water inlet of the heat exchanger when the temperature of the working fluid is equal to or more than a second temperature that is higher than the first temperature.   
     
     
         5 . The fluid temperature adjustment device according to  claim 4 , wherein
 the switching valve includes
 a first input port that communicates with the first flow path, 
 a second input port that communicates with the second flow path, 
 an output port that communicates with the cooling water inlet of the heat exchanger, 
 a spool that moves in an axial direction to selectively communicate between one of the first and second input ports and the output port, 
 a spring that urges the spool in the axial direction, and 
 a thermally expandable material attached to the spool; and 
   the thermally expandable material permits the spool to be urged by the spring to be moved, and moves the spool against an urging force of the spring, in accordance with the temperature of the working fluid.   
     
     
         6 . The fluid temperature adjustment device according to  claim 2 , wherein
 the switching valve communicates between the first flow path and the cooling water inlet of the heat exchanger when the temperature of the working fluid is less than a first temperature, and communicates between the second flow path and the cooling water inlet of the heat exchanger when the temperature of the working fluid is equal to or more than a second temperature that is higher than the first temperature.   
     
     
         7 . The fluid temperature adjustment device according to  claim 6 , wherein
 the switching valve includes
 a first input port that communicates with the first flow path, 
 a second input port that communicates with the second flow path, 
 an output port that communicates with the cooling water inlet of the heat exchanger, 
 a spool that moves in an axial direction to selectively communicate between one of the first and second input ports and the output port, 
 a spring that urges the spool in the axial direction, and 
 a thermally expandable material attached to the spool; and 
   the thermally expandable material permits the spool to be urged by the spring to be moved, and moves the spool against an urging force of the spring, in accordance with the temperature of the working fluid.   
     
     
         8 . The fluid temperature adjustment device according to  claim 1 , wherein the third flow path is merged with the circulation flow path at a location downstream of a branched portion between the circulation flow path and the second flow path and upstream of the engine. 
     
     
         9 . The fluid temperature adjustment device according to  claim 8 , wherein
 the switching valve includes
 a first input port that communicates with the first flow path, 
 a second input port that communicates with the second flow path, 
 an output port that communicates with the cooling water inlet of the heat exchanger, 
 a spool that moves in an axial direction to selectively communicate between one of the first and second input ports and the output port, 
 a spring that urges the spool in the axial direction, and 
 a thermally expandable material attached to the spool; and 
   the thermally expandable material permits the spool to be urged by the spring to be moved, and moves the spool against an urging force of the spring, in accordance with the temperature of the working fluid.