Washing machine

Abstract

A washing machine including a drum provided with a plurality of recess portions each provided in a polygonal pyramid recessed from one of an inner surface and an outer surface of the drum toward the remaining of the inner side and the outer side of the drum, and a plurality of through-holes configured to receive and discharge wash water, the recess portion including a polygonal side provided in a form of a polygon, and a plurality of edges extending from corners of the polygonal side to meet at a vertex of the recess portion, and the through-hole is formed through at least one of sides that form the polygonal side, thereby improving the washing performance due to the recess portion that makes a friction of the laundry with the sides of the recess portion.

What is claimed is: 
     
         1 . A washing machine comprising:
 a tub;   a drum disposed at an inside the tub; and   a driving apparatus configured to rotate the drum,   wherein the drum comprises a plurality of recess portions each provided in a form of a polypyramid recessed from one of an inner surface and an outer surface of the drum toward the remaining of the inner side and the outer side of the drum, and a plurality of through-holes configured to drain water,   the recess portion comprises a polygonal side provided in a form of a polygon, and a plurality of edges extending from corners of the polygonal side to meet at a vertex of the recess portion, and   the through-hole is formed through at least one of sides that form the polygonal side.   
     
     
         2 . The washing machine of  claim 1 , wherein the drum is inclinedly disposed to have a front thereof higher than a rear thereof. 
     
     
         3 . The washing machine of  claim 1 , wherein each of the plurality of recess portions is recessed in a form of a quadrangular pyramid so as to have a quadrangle side. 
     
     
         4 . The washing machine of  claim 3 , wherein the plurality of through-holes are formed through two of four sides forming the quadrangle side, the two sides opposite to each other in a rotation direction of the drum. 
     
     
         5 . The washing machine of  claim 3 , wherein the plurality of through-holes are formed through two of four sides forming the quadrangle side, the two sides opposite to each other in a direction of a shaft of the drum. 
     
     
         6 . The washing machine of  claim 3 , wherein the plurality of through-holes are formed through each of four sides forming the quadrangle side. 
     
     
         7 . The washing machine of  claim 1 , wherein the plurality of through-hole are formed through at least one of middle portions of four sides forming the polygonal side. 
     
     
         8 . The washing machine of  claim 1 , wherein the plurality of recess portions are formed adjacent to one another, and the through-hole is formed through a side that is shared by adjacent two recess portions of the plurality of the recess portions. 
     
     
         9 . A washing machine comprising:
 a tub;   a drum disposed at an inside the tub; and   a driving apparatus configured to rotate the drum,   wherein the drum comprises a plurality of recess portions provided in a form of a polypyramid recessed from an inner surface to an outer surface of the drum, and a plurality of through-holes formed through vertexes of the plurality of recess portions to drain water,   the recess portion comprises a polygonal side provided in a form of a polygon, a plurality of edges extending from corners of the polygonal side to meet at the vertex of the recess portion, and a plurality of side surfaces each provided between corresponding ones of the plurality of edges, and   two of the plurality of side surfaces opposite to each other are inclined with different angels.   
     
     
         10 . The washing machine of  claim 10 , wherein the two of the plurality of side surfaces inclined with the different angles are disposed opposite to each other in a direction of a shaft of the drum. 
     
     
         11 . The washing machine of  claim 10 , wherein a side surface provided at a rear of the drum among the plurality of side surfaces has an inclination angle smaller than an inclination angle of a side surface provided at a front of the drum among the plurality of side surfaces. 
     
     
         12 . The washing machine of  claim 9 , wherein the two of the plurality of side surfaces inclined with the different angles are disposed opposite to each other in a circumferential direction of the drum. 
     
     
         13 . The washing machine of  claim 12 , wherein a side surface provided at an upstream in a rotation direction of the drum among the plurality of side surfaces has an inclination angle smaller than an inclination angle of a side surface provided at a downstream in the rotation direction of the drum among the plurality of side surfaces. 
     
     
         14 . The washing machine of  claim 9 , wherein the recess portion is provided in a quadrangular pyramid including four edges and four side surfaces formed between corresponding ones of the four edges.