Damper and washing machine having the same

Abstract

A damper includes: a cylinder having a receiving space with a predetermined depth in a longitudinal direction on one side thereof; a rod inserted to be movable relatively in a longitudinal direction in the receiving space of the cylinder; a friction surface formed at one side of the cylinder and the rod; a friction member positioned at the cylinder or the rod and rubbing on the friction surface; a thermally deformable member being deformed according to a change in a temperature to make the friction member be tightly attached to the friction surface or separated therefrom; and a heating unit for thermally deforming the thermally deformable member. The damper absorbs the small and large amount of vibrations to thereby prevent transfer of vibration to other parts.

What is claimed is:  
     
         1 . A damper comprising: 
 a cylinder having a receiving space with a predetermined depth in a longitudinal direction on one side thereof;    a rod inserted to be movable relatively in a longitudinal direction in the receiving space of the cylinder;    a friction surface formed at one side of the cylinder and the rod;    a friction member positioned at the cylinder or the rod and rubbing on the friction surface;    a thermally deformable member being deformed according to a change in a temperature to make the friction member be tightly attached to the friction surface or separated therefrom; and    a heating unit for thermally deforming the thermally deformable member.    
     
     
         2 . The damper of  claim 1 , wherein the receiving space of the cylinder has a cylindrical shape, and the friction surface (FS) is formed at an inner circumferential surface of the receiving space of the cylinder.  
     
     
         3 . The damper of  claim 1 , wherein the friction member has a ring shape with a predetermined thickness and length.  
     
     
         4 . The damper of  claim 3 , wherein the annular friction member has one side cut out with a predetermined width.  
     
     
         5 . The damper of  claim 1 , wherein if the thermally deformable member is heated at a high temperature, it contracts and separates the friction member from the friction surface, whereas if the thermally deformable member is not heated with no heat applied thereto, it expands to make the friction member be tightly attached to the friction surface and generate a friction force.  
     
     
         6 . The damper of  claim 1 , wherein if the thermally deformable member is heated at a high temperature, it expands to make the friction member be tightly attached to the friction surface and generate a friction force, whereas if the thermally deformable member is not heated with no heat applied thereto, it contracts and separates the friction member from the friction surface.  
     
     
         7 . The damper of  claim 1 , wherein the thermally deformable member is a shape memory alloy.  
     
     
         8 . The damper of  claim 7 , wherein the shape memory alloy has a ring shape with a predetermined thickness and length, of which one side is cut out with a predetermined width.  
     
     
         9 . The damper of  claim 1 , wherein the thermally deformable member is made of bi-metal.  
     
     
         10 . The damper of  claim 9 , wherein the bi-metal comprises: 
 a first annular metal having a predetermined thickness and length; and    a second annular metal having a predetermined thickness and length, coupled to an outer circumferential surface of the first annular metal, and being made of a material with a different thermal expansion coefficient from the first annular metal.    
     
     
         11 . The damper of  claim 10 , wherein the first and second annular metals have one side, respectively, cut out with a predetermined width.  
     
     
         12 . The damper of  claim 1 , wherein the heating unit is a coil heater.  
     
     
         13 . The damper of  claim 1 , wherein the thermally deformable member is coupled to an outer side of the rod positioned inside the receiving space of the cylinder, the heating unit is mounted inside the rod, and the friction member is coupled to an outer side of the thermally deformable member and faces the friction surface (FS).  
     
     
         14 . The damper of  claim 13 , wherein there is a predetermined interval between the thermally deformable member and the rod.  
     
     
         15 . The damper of  claim 13 , wherein a coupling groove is formed with a predetermined depth and length at an outer side of the rod, into which the thermally deformable member is inserted, and a coupling groove is formed with a predetermined depth and length at an outer side of the thermally deformable member, into which the friction member is inserted.  
     
     
         16 . A washing machine including a cabinet having an internal space in a predetermined shape and a tub positioned inside the cabinet and filled with washing water, comprising: 
 a cylinder having a receiving space with a predetermined depth in a longitudinal direction at one side and being coupled to the cabinet or to the tub at the other side;    a rod having one side inserted to be movable relatively in a longitudinal direction in the receiving space of the cylinder and the other side coupled to the cabinet or the tub;    a friction surface formed at the cylinder or at the rod;    a friction member positioned at the cylinder or at the rod so as to rub on the friction surface;    a thermally deformed member for making the friction member be tightly attached to the friction surface or separated therefrom by being deformed according to a temperature change; and    is a heating unit for thermally deforming the thermally deformable member.