Reservoir tank for vehicle

A reservoir tank, comprising:

• a first chamber configured such that coolant circulates through the first chamber or is stored in the first chamber;
• a second chamber provided on a side and spaced apart from the first chamber and configured such that coolant having a different temperature from the coolant stored in the first chamber circulates through the second chamber or is stored in the second chamber;
• a first partition and a second partition provided in a space between the first chamber and the second chamber to separate the first chamber and the second chamber from each other, and spaced apart from and facing each other;
• and
• a middle chamber defined in a space between the first partition and the second partition and configured such that the coolant from the first chamber or the second chamber circulates through the middle chamber or is stored in the middle chamber, thereby providing a heat buffer between the first chamber and the second chamber,
• wherein an input channel through which the coolant is introduced to the first chamber or the second chamber and an output channel through which the coolant is discharged from the first chamber or the second chamber are provided outside the first chamber or the second chamber, the input channel and the output channel being provided integrally with the first chamber or the second chamber, and
• wherein a coupling recess to which a pump is coupled is provided integrally with the first chamber or the second chamber, in a position outside a lower portion of the first chamber or the second chamber, and when the output channel is connected to the coupling recess and the pump coupled to the coupling recess operates, the coolant circulates through the input channel or the output channel.