Tray driving apparatus for a microwave oven and a microwave oven having the same

Abstract

A tray driving apparatus for a microwave oven and a microwave oven having the same including a speed changing unit for enhancing the cooking quality by periodically changing the rotational speed of the tray to more evenly radiate a microwave to food. The speed changing means includes a driving gear unit having a plurality of driving gears and mounted to the driving shaft; and a driven gear unit having a plurality of driven gears corresponding to respective driving gears of the driving gear unit, and mounted to the driven shaft. The gears of any one of the driving gear unit and the driven gear unit are portion gears which are gears having gear teeth on respective portions of outer peripheries thereof, the gear teeth of the portion gears are alternately disposed to each other one on another. Accordingly, upon a rotation of the driving shaft, each portion gear of any one of the driving gear unit and the driven gear unit are alternately meshed with a corresponding gear of the other one of the driving gear unit and the driven gear unit, to thereby change the rotational speed of the tray.

1. A tray driving apparatus of a microwave oven, comprising:
 a driving source for rotating a tray disposed in a cooking chamber of said microwave oven;  
 a driving shaft rotated by the driving source;  
 a driven shaft connected to the tray and rotated together with the tray; and  
 speed changing means for changing the rotational speed of the tray by changing the ratio of the rotational speed transmitted from the driving shaft to the driven shaft;  
 said speed changing means including  comprising: 
 a driving gear unit having a plurality of driving gears, and  mounted to  on the driving shaft; and  
 a driven gear unit having a plurality of driven gears corresponding to respective driving gears of the driving, ear  gear unit, and  mounted to  on the driven shaft;  
 wherein gears of any one of the driving rear  gear unit and the driven gear unit are portion gears which are gears  having gear teeth on respective portions of outer peripheries thereof, so that, upon a rotation of the driving shaft, each portion gear of any one of the driving gear unit and the driven gear unit are alternately meshed with a corresponding gear of the other one of the driving gear unit and the driven gear unit, to thereby change the rotational speed of the tray.  
 
 
     
     
       2. The tray driving apparatus of a microwave oven as claimed in  claim 1 , wherein the gear teeth of each portion gear are formed on a plurality of portions of the outer periphery of each portion gear. 
     
     
       3. A microwave oven, comprising:
 a body in which a cooking chamber is formed;  
 a high frequency generator for generating and radiating a high frequency into the interior of the cooking chamber;  
 a tray mounted to be rotated on the bottom of the cooking chamber in order for food to be securely placed;  
 a driving source for providing a driving force for rotating the tray;  
 a driving shaft rotated by the driving source;  
 a driven shaft connected to the tray and rotated together with the tray;  
 a driving gear unit having a plurality of driving gears and mounted to the driving shaft; and  
 a driven gear unit having a plurality of driven gears corresponding to the plurality of driving gears, and mounted to the driven shaft;  
 wherein gears of any one of the driving gear unit and the driven gear unit are portion gears which are gears having gear teeth on respective portions of outer peripheries thereof, so that, upon a rotation of the driving shaft, each portion gear of any one of the driving gear unit and the driven gear unit is alternately meshed with a corresponding gear of the other one of the driving gear unit and the driven gear unit, to thereby change the rotational speed of the tray.  
 
     
     
       4. A tray driving apparatus of a microwave oven, comprising:
 a tray;  
 a tray shaft fixed to said tray and rotatably mounted on a cooking chamber ;  
 a plurality of tray gears fixed to said tray shaft;  
 a driving source mounted on said cooking chamber ;  
 a driving shaft connected to said driving source; and  
 first and second driving gears fixed to said driving shaft, and having a tooth  toothed portion and a toothless portion, disposed to be meshed with respective tray gears, each tooth  toothed portion of said first and second driving gears alternatively meshed with said respective tray gears while said driving shaft rotates by said driving source.  
 
     
     
       5. The tray driving apparatus of  claim 4 , with said tray gears being different from each other in diameter. 
     
     
       6. The tray driving apparatus of  claim 4 , with said first and second driving gears being different from each other in diameter. 
     
     
       7. The tray driving apparatus of  claim 4 , with the tooth  toothed portion of said first driving gear being coupled to one of said tray gears while the tooth  toothed portion of said second gear disconnected from the other one of said tray gears. 
     
     
       8. The tray driving apparatus of  claim 4 , with the tooth  toothed portion of said first driving gear disposed to be coupled to one of said tray gears before the tooth  toothed portion of said second gear is disconnected from the other one of said tray gears. 
     
     
       9. The tray diving  driving apparatus of  claim 4 , with first and second driving gear having said tooth  toothed portion formed on one portion of an outer peripheral surface of said first and second driving gear while said toothless portion is formed on the other  a remaining portion of said outer peripheral surface of said first and second driving gear. 
     
     
       10. The tray driving apparatus of  claim 4 , wherein the tooth  toothed portion of said first driving gear and the toothless portion of said second driving gear are formed on one area around said driving shaft while the toothless portion of said first driving gear and the tooth  toothed portion of said second driving gear are formed on the other area around said driving shaft. 
     
     
       11. The tray driving apparatus of  claim 4 , with said tray rotating with a first rotational speed when the tooth  toothed portion of said first driving gear is coupled to the corresponding tray gear and with a second rotational speed when the tooth  toothed portion of said second driving gear is coupled to the corresponding tray gear while said driving shaft rotates  is rotated by said driving source. 
     
     
       12. A tray driving apparatus of a microwave oven, comprising:
 a tray disposed in a cooking chamber;  
 a tray shaft coupled to said tray and rotatably mounted on a cooking chamber ;  
 a tray gear unit fixed to said tray shaft, having a first gear tooth  toothed portion and a second gear tooth  toothed portion;  
 a driving source mounted on said cooking chamber ;  
 a driving shaft coupled to said driving source;  
 a driving gear unit fixed to said driving shaft, having a third gear tooth  toothed portion disposed to be meshed with said first gear tooth  toothed portion and a fourth gear tooth  toothed portion disposed to be meshed with said second gear tooth  toothed portion; and  
 said third gear tooth  toothed portion and said fourth gear tooth  toothed portion alternatively meshed with the corresponding first gear tooth  toothed portion and second gear tooth  toothed portion while said driving shaft rotates by said driving source.  
 
     
     
       13. The tray driving apparatus of  claim 12 , with said tray gear unit comprising a first gear having said first gear tooth  toothed portion and a second gear having said second gear tooth  toothed portion, said first and second gears fixed to said tray shaft and rotating about an axis passing through a center of said tray shaft. 
     
     
       14. The tray driving apparatus of  claim 13 , with said first and second gears being different from each other in diameter. 
     
     
       15. The tray driving apparatus of  claim 12 , with said driving gear comprising a third gear having said third gear tooth  toothed portion and a fourth gear having said fourth gear tooth  toothed portion, said third and fourth gears fixed to said driving shaft and rotating about an axis passing through a center of said driving shaft. 
     
     
       16. The tray driving apparatus of  claim 15 , with said third and fourth gears being different from each other in diameter. 
     
     
       17. The tray driving apparatus of  claim 15 , with said third gear tooth  toothed portion foamed on a portion of an outer peripheral surface of said third gear in one area around said driving shaft while said fourth gear tooth  toothed portion is formed on a portion of an outer peripheral surface of said fourth gear in the other area around said driving shaft. 
     
     
       18. The tray driving apparatus of  claim 17 , with said third gear tooth  toothed portion of said third gear meshed with said first geartooth  toothed portion while said fourth gear tooth  toothed portion of said fourth gear is disconnected to said second gear tooth  toothed portion. 
     
     
       19. The tray driving apparatus of  claim 12 , with said tray rotating with a first rotational speed when third gear tooth  toothed portion is meshed with said first gear tooth  toothed portion and a second rotational speed when said fourth gear tooth  toothed portion is meshed with said second gear portion while said driving shaft rotates by said driving source. 
     
     
       20. A microwave oven, comprising:
   a body having an interior cooking chamber;        a high frequency generator radiating high frequency energy into said cooking chamber;        a tray mounted on a bottom of said cooking chamber;        a driving shaft;        a driven shaft rotatably connected to said tray;        a first drive unit comprising a plurality of driving gears mounted on said driving shaft;        a second drive unit comprising a plurality of driven gears mounted on the driven shaft operationally aligned to mesh in different gear ratios with different ones of said driving gears; and        a first one of said plurality of driving gears and said plurality of driven gears comprising an assembly of sector gears having gear teeth along different respective arcuate portions of outer peripheries thereof alternately meshing with corresponding gears of a second one of said plurality of driving gears and said plurality of driven gears to vary rotational speeds of said tray in dependence upon said ratios.     
     
     
       21. A microwave process, comprising:
   positioning a tray within an interior cooking chamber of a microwave oven;        radiating high frequency energy into said cooking chamber; and        varying rotational speeds of said tray within said cooking chamber while radiating high frequency energy into said cooking chamber by successively meshing different ones of a first plurality of gears comprised of sector gears providing different arcuate sectors of rotation with operationally aligned gears of a second plurality of gears.     
     
     
       22. The microwave process of  claim 21 , comprised of varying said rotational speeds by alternately meshing said sector gears and said operationally aligned gears in different gear ratios. 
     
     
       23. The microwave process of  claim 21 , comprised of:
   assembling a first one of a plurality of driving gears and a plurality of driven gears from a plurality of said sector gears having gear teeth along different respective arcuate sectors of outer peripheries thereof;        aligning said plurality of driving gears with different corresponding ones of said plurality of driven gears in different gear ratios; and        alternately meshing corresponding gears of said first plurality of driving gears and said plurality of driving gears to said vary rotational speeds of said tray in dependence upon said ratios.     
     
     
       24. A microwave process, comprising:
   positioning a tray within an interior cooking chamber of a microwave oven;        radiating high frequency energy into said cooking chamber;        a driving shaft;        a driven shaft rotatably connected to said tray;        driving a first drive unit comprising a plurality of driving gears with different corresponding driven gears of a second drive unit operationally aligned to mesh in different gear ratios with different ones of said driving gears, where a first one of said plurality of driving gears and said plurality of driven gears comprise an assembly of sector gears having gear teeth along different respective arcuate portions of outer peripheries thereof; and        alternately meshing said sector gears with corresponding gears of a second one of said plurality of driving gears and said plurality of driven gears to vary said rotational speeds of said tray in dependence upon said ratios.     
     
     
       25. A microwave oven, comprising:
   a body providing an interior cooking chamber;        a high frequency generator radiating high frequency energy into said cooking chamber;        a tray mounted within said cooking chamber; and        a drive unit comprised of a plurality of sector gears aligned to mesh sequentially with a second plurality of gears, with said drive unit operationally engaging said tray and automatically varying rates of rotation of said tray while said tray rotates through successive arcuate sectors of rotation within said cooking chamber.     
     
     
       26. The oven of  claim 25 , with said drive unit rotating said tray at different said rates of rotation as said tray travels through said successive arcuate sectors. 
     
     
       27. The oven of  claim 25 , with said drive unit comprising:
   a driven shaft connected to rotate said tray at said different rates of rotation;        a driving shaft;        a first assembly comprised of a plurality of driven gears mounted on said driven shaft; and        a second assembly comprised of a plurality of driving gears mounted on said driving shaft and operationally aligned to mesh over different ones of said successive arcuate sectors in different gear ratios with different ones of said driven gears.     
     
     
       28. The oven of  claim 25 , with said drive unit comprising:
   a driven shaft connected to rotate said tray at said different rates of rotation;        a driving shaft;        a first assembly comprised of a plurality of driven gears coaxially mounted on said driven shaft;        a second assembly comprised of a plurality of driving gears coaxially mounted on said driving shaft and operationally aligned to mesh in different gear ratios with different ones of said driven gears over different ones of said arcuate sectors; and        one of said first assembly and said second assembly comprising a plurality of sector gears bearing teeth along different peripheral sectors, alternately meshing with corresponding gears of a second one of said first assembly and said second assembly, to vary said rates of rotation of said tray in dependence upon said ratios.     
     
     
       29. A microwave process, comprising:
   positioning a tray to rate around an interior of a cooking chamber in a microwave oven;        radiating high frequency energy into said cooking chamber; and        varying rotational speeds of said tray within said cooking chamber by meshing a plurality of sector gears aligned to mesh sequentially with different corresponding ones of a second plurality of gears to automatically change said rotational speeds periodically while said tray rotates through successive arcuate sectors of rotation within said cooking chamber.     
     
     
       30. A microwave process of  claim 28 , further comprised of alternately meshing different ones of said plurality of driving gears with corresponding ones of said second plurality of gears in different gear ratios. 
     
     
       31. The process of  claim 28 , further comprised of varying said rotational speeds by alternately meshing different ones of a first plurality of gears coaxially mounted on a shaft with corresponding ones of a plurality of sector gears bearing teeth along different arcuate peripheries thereof, as said tray rotated through said successive arcuate sectors.