Flat heat pipe with sectional differences and method for manufacturing the same

Abstract

The present invention provides a flat heat pipe with sectional differences and a method for manufacturing the same. The heat pipe has a flat hollow pipe body. A working fluid is sealed in the pipe body. The pipe body is provided along its length with a plurality of flat sectional difference portions having different widths. A connecting portion is formed between the sectional difference portions. The inner wall of the pipe body is formed with a plurality of grooves. The pitch between the grooves in the sectional difference portion of a relatively large width is larger than the pitch between the grooves in the sectional difference portion of a relatively small width.

1 . A flat heat pipe with sectional differences, configured to have a flat hollow pipe body, a working fluid being sealed in the pipe body, the pipe body being provided along its length with a plurality of flat sectional difference portions having different widths, a connecting portion being formed between each sectional difference portions,
 wherein an inner wall of the pipe body is formed with a plurality of grooves, a pitch between the grooves in the sectional difference portion of a relatively large width is larger than a pitch between the grooves in the sectional difference portion of a relatively small width.   
     
     
         2 . The flat heat pipe with sectional differences according to  claim 1 , wherein the connecting portion is integrally formed between each sectional difference portions to connect the respective sectional difference portions. 
     
     
         3 . The flat heat pipe with sectional differences according to  claim 1 , wherein the sectional difference portion having a relatively large width is configured to act as an evaporating portion of the heat pipe. 
     
     
         4 . The flat heat pipe with sectional differences according to  claim 1 , wherein the sectional difference portion having a relatively small width is configured to act as a heat-transmitting portion of the heat pipe. 
     
     
         5 . The flat heat pipe with sectional differences according to  claim 1 , wherein each of the grooves is formed with sintered powder. 
     
     
         6 . A method for manufacturing a flat heat pipe with sectional differences, including steps of:
 a) draw-forming a tubular hollow pipe body, the pipe body having one outer diameter, forming a plurality of grooves on an inner wall of the pipe body;   b) making the pipe body to have a plurality of outer diameters along its length to thereby form a plurality of tubular sectional difference portions on the pipe body;   c) degassing the interior of the pipe body into vacuum and sealing both ends of the pipe body; and   (d) pressing the respective sectional difference portions of the pipe body into flat.   
     
     
         7 . The method according to  claim 6 , wherein any one or part of the sectional difference portions is narrowed by a pipe-narrowing process in the step b). 
     
     
         8 . The method according to  claim 7 , wherein an un-narrowed part of the sectional difference portions is widened by a pipe-widening process. 
     
     
         9 . The method according to  claim 6 , wherein any one or part of the sectional difference portions is widened by a pipe-widening process in the step b). 
     
     
         10 . The method according to  claim 9 , wherein an un-widened part of the sectional difference portions is narrowed by a pipe-narrowing process. 
     
     
         11 . The method according to  claim 6 , wherein after the pipe body is formed with the plurality of sectional difference portions in the step b), metal powder is filled in each groove of the pipe body, the metal powder is sintered to become sintered powder.