Cooling circuit and oil cooler

Abstract

A cooling circuit includes a first coolant passage in which a coolant flows, a second coolant passage in which the coolant flows, a thermostat, and an oil cooler configured to heat or cool oil. The thermostat interrupts a flow of the coolant flowing through the first coolant passage when a temperature of the coolant flowing into the thermostat is lower than a predetermined temperature, and allows the coolant to flow through the first coolant passage when the temperature of the coolant is at or above a predetermined temperature. The oil cooler includes a first coolant inflow port, a first coolant outflow port, a second coolant inflow port, and a second coolant outflow port. The oil cooler heats or cools the oil by heat exchange between the coolant flowing from the first coolant inflow port or/and the second coolant inflow port and the oil.

What is claimed is: 
     
         1 . A cooling circuit comprising:
 a first coolant passage in which a coolant flows;   a second coolant passage in which the coolant flows;   a thermostat configured to interrupt a flow of the coolant flowing through the first coolant passage when a temperature of coolant flowing into the thermostat is lower than a predetermined temperature, and to allow the coolant to flow through the first coolant passage when the temperature of the coolant is at or above a predetermined temperature; and   an oil cooler configured to heat or cool oil, wherein the oil cooler includes:   a first coolant inflow port into which the coolant flowing in the first coolant passage flows;   a second coolant inflow port into which the coolant flowing in the second coolant passage flows;   an inner passage provided therein to communicate with the first coolant inflow port and the second coolant inflow port;   a first coolant outflow port, provided to communicate with the inner passage, through which the coolant having passed through the inner passage flows out of the oil cooler and flows into the first coolant passage; and   a second coolant outflow port, provided to communicate with the inner passage, through which the coolant having passed through the inner passage flows into the second coolant passage,   the inner passage of the oil cooler is configured to perform heat exchange between the coolant flowing therein and the oil, and   the first coolant passage and the second coolant passage are coupled to the oil cooler, to cause the coolant in the second coolant passage flows into the inner passage only through the second coolant inflow port when the thermostat interrupts the flow of the coolant flowing through the first coolant passage, and to cause the coolant in the first coolant passage and the second coolant passage flows into the inner passage through both of the first coolant inflow port and the second coolant inflow port when the thermostat allows the flow of the coolant flowing through the first coolant passage.   
     
     
         2 . The cooling circuit according to  claim 1  further comprising:
 a bypass passage that couples the first coolant inflow port to the first coolant passage; and 
 a flow regulator provided in the bypass passage and configured to regulate a flow of the coolant flowing from the first coolant inflow port toward the first coolant passage. 
 
     
     
         3 . The cooling circuit according to  claim 2 , wherein
 the flow regulator is a check valve.   
     
     
         4 . The cooling circuit according to  claim 1 , wherein
 the oil cooler is configured to have a flow direction of the coolant flowing from the first coolant inflow port to the first coolant outflow port, which intersects with a flow direction of the oil flowing in the oil cooler.   
     
     
         5 . The cooling circuit according to  claim 1 , wherein
 the oil is used for an transmission in a vehicle.   
     
     
         6 . The cooling circuit according to  claim 1 , wherein
 the oil is used for a power machine in a vehicle.   
     
     
         7 . An oil cooler configured by a plurality of plates laminated to define an oil passage through which an oil flows and a coolant passage through which coolant flows, the oil passage and the coolant passage being arranged alternatively, the oil cooler comprising
 a plurality of coolant plates defining the coolant passage, each of the coolant plate includes:
 an inner passage in which the coolant flows; 
 a first coolant inflow passage through which the coolant flows into the inner passage; 
 a second coolant inflow passage through which the coolant flows into the inner passage; 
 a first coolant outflow passage through which the coolant in the inner passage flows out; and 
 a second coolant outflow passage through which the coolant in the inner passage flows out, 
   the inner passage is configured to communicate with both the first coolant inflow passage and the second coolant inflow passage and to communicate with the first coolant outflow passage and the second coolant outflow passage, to cause the coolant flows into the inner passage only through the second coolant inflow port when a flow of the coolant flowing into the first coolant inflow passage is closed, and to cause the coolant flows into the inner passage through both of the first coolant inflow port and the second coolant inflow port when the coolant flows into the first coolant inflow passage and the second coolant inflow passage.   
     
     
         8 . The oil cooler according to  claim 7 , wherein
 the coolant plate further includes a flow resistance applying part configured to cause a flow resistance of the coolant flowing in a first direction from the first coolant inflow passage toward the first coolant outflow passage to be different from a flow resistance of the coolant flowing in a second direction from the second coolant inflow passage toward the second coolant outflow passage.   
     
     
         9 . The oil cooler according to  claim 8 , wherein
 the flow resistance applying part is an offset fin that includes a plurality of cut-and-raised parts, formed by cutting and raising a plate partially and lined in the first direction, and the cut-and-raised parts adjacent to each other in the first direction are offset from each other.   
     
     
         10 . The oil cooler according to  claim 8 , wherein
 the cut-and-raised parts adjacent to each other in the first direction are offset in the second direction that is perpendicular to the first direction,   the first coolant inflow passage is located opposite to the first coolant outflow passage in the first direction with respect to the offset fin, and   the second coolant inflow passage is located at an opposite side of the second coolant outflow passage with respect to the offset fin in a third direction that bisects an angle between the first direction and the second direction.   
     
     
         11 . The oil cooler according to  claim 7 , further comprising
 a rib provided between the first coolant inflow passage and the second coolant inflow passage to restrict the coolant from flowing in shortcut between the first coolant inflow passage and the second coolant inflow passage.   
     
     
         12 . The oil cooler according to  claim 7 , wherein
 the second coolant inflow passage causes the coolant to flow toward the second coolant outflow passage in a direction that intersects with a flow direction of the oil.