Electronic thermostat

Abstract

The present invention relates generally to an electronic thermostat. More particularly, the present invention relates to an electronic thermostat configured to operate a valve by using expansion pressure of a thermally expandable material as a heater generates heat, wherein foreign substances are prevented from being accumulated in a guide cap, thus preventing malfunction of the valve from occurring. The electronic thermostat configured to control flow of a coolant by using a piston reciprocating in response to expansion and contraction of a thermally expandable material includes: a casing; a heater; a guide; the piston; a sealing member; a guide cap; and a valve, wherein the guide cap has a discharge hole formed at a lower end thereof.

What is claimed is: 
     
         1 . An electronic thermostat configured to control flow of a coolant by using a piston reciprocating in response to expansion and contraction of a thermally expandable material, the electronic thermostat comprising:
 a casing having a space defined therein to accommodate the thermally expandable material;   a heater inserted into the thermally expandable material filled in the space of the casing and generating heat upon application of an external power source;   a guide provided at a lower portion of the casing and bearing an expansion pressure of the thermally expandable material that expands;   the piston provided to be movable upward and downward along an inner peripheral surface of the guide;   a sealing member provided at a lower end portion of the casing and sealing the thermally expandable material in the casing;   a guide cap provided to be movable upward and downward on a passage of the coolant along an outer peripheral surface of the guide by a pressing force exerted thereon by the piston; and   a valve coupled to the guide cap to open and close the passage,   wherein the guide cap has a discharge hole formed at a lower end thereof.   
     
     
         2 . The electronic thermostat of  claim 1 , further comprising:
 a ring-shaped member provided between the guide cap and the guide.   
     
     
         3 . The electronic thermostat of  claim 2 , wherein the guide has a cylindrical seal cap mounted to a lower end thereof. 
     
     
         4 . The electronic thermostat of  claim 3 , wherein the seal cap includes:
 a sealing portion being in surface contact with an outer peripheral surface of the piston; and   a coupling portion coupled to the lower end of the guide, wherein   the coupling portion has a groove structure centrally formed on an inner peripheral surface of the seal cap, and   the guide has a protrusion formed at the lower end thereof to correspond to the groove structure.   
     
     
         5 . The electronic thermostat of  claim 4 , wherein the groove structure and the protrusion are configured such that an inner diameter and an outer diameter thereof increase upward, respectively.