Variable damping type damper and washing machine having the same

Abstract

A variable damping type damper and a washing machine having the same comprise: a cylinder of which one side is provided with a receiving space having a certain depth and another side thereof is coupled to the cabinet or the tub; a rod of which one side is relative-movably inserted into the receiving space of the cylinder and another side thereof is coupled to the cabinet or the tub; a guide bar provided at an end portion of the rod; a variable volume frictional means expanded and contracted in itself by a difference of flow amount introduced/exhausted into/from an inner space by being coupled to the guide bar, and adhered/detached to/from an inner circumferential surface of the receiving space of the cylinder; a volume type slider performing a relative movement with the variable volume frictional means by being slidably inserted into the guide bar, for causing fluid flow inside the variable volume frictional means; and a frictional member fixedly coupled to the volume type slider for generating a frictional force with the inner circumferential surface of the receiving space of the cylinder. According to this, steady state vibration and transient state vibration generated from a tub assembly during an entire process for washing laundry are prevented from being transmitted to a cabinet, thereby minimizing noise leaked to outside.

What is claimed is:  
     
         1 . A variable damping type damper comprising: 
 a cylinder provided with a receiving space having a certain depth at one side thereof;    a rod relative-movably inserted into the receiving space of the cylinder;    a guide bar provided at the rod;    a variable volume frictional means expanded and contracted in itself by a difference of flow amount introduced/exhausted into/from an inner space by being coupled to the guide bar, and adhered/detached to/from an inner circumferential surface of the receiving space of the cylinder;    a volume type slider performing a relative movement with the variable volume frictional means by being slidably inserted into the guide bar, for causing fluid flow inside the variable volume frictional means; and    a frictional member fixedly coupled to the volume type slider for generating a frictional force with the inner circumferential surface of the receiving space of the cylinder.    
     
     
         2 . The damper of  claim 1 , wherein the guide bar has a certain length and has an outer diameter smaller than an outer diameter of the rod.  
     
     
         3 . The damper of  claim 1 , wherein a penetration hole connected to the receiving space is formed at one side of a circumferential wall of the cylinder.  
     
     
         4 . The damper of  claim 1 , wherein an inner circumferential surface of the receiving space of the cylinder is a frictional surface.  
     
     
         5 . The damper of  claim 1 , wherein the variable volume frictional means comprises: 
 a cylindrical body having a certain outer diameter and a length and having one side wall coupled to an end portion of the guide bar thus to be volume-varied in itself;    an inflow path formed at one side of the cylindrical body;    an outflow path having less air flow amount than the inflow path and formed at another side of the cylindrical body;    a first valve for controlling a flow of air introduced into the cylindrical body; and    a first friction ring coupled to an outer circumferential surface of the cylindrical body.    
     
     
         6 . The damper of  claim 5 , wherein a circumferential wall of the cylindrical body is formed of a flexible membrane.  
     
     
         7 . The damper of  claim 5 , wherein the inflow path is formed at a side wall of a cylindrical body to which an end of a rod is coupled, and the outflow path is formed at an opposite side wall of the cylindrical body.  
     
     
         8 . The damper of  claim 7 , wherein the inflow path is formed of a plurality of penetration holes having the same inner diameter, and the outflow path is formed of penetration holes having the number less than the number of the penetration holes of the inflow path.  
     
     
         9 . The damper of  claim 5 , wherein the first valve is mounted at the inflow path.  
     
     
         10 . The damper of  claim 5 , wherein the first friction ring is formed as a circular shape having a certain thickness and width, and is expandable in a circumferential direction.  
     
     
         11 . The damper of  claim 5 , wherein the first friction ring does not receive a vertical force with an inner circumferential surface of the receiving space of the cylinder when the cylindrical body is not expanded in itself, and receives the vertical force when the cylindrical body is expanded in itself.  
     
     
         12 . The damper of  claim 1 , wherein the volume type slider comprises: 
 a cylindrical body having a certain outer diameter and length and provided with an insertion hole for penetration-inserting the guide bar at the center thereof;    a penetration path for penetrating the cylindrical body; and    a second valve for opening and closing the penetration path.    
     
     
         13 . The damper of  claim 1 , wherein a frictional force due to a relative movement between the frictional member and an inner circumferential surface of the receiving space of the cylinder is generated at the time of exceeding a preset vibration width.  
     
     
         14 . The damper of  claim 1 , wherein a flexible tube for preventing collision and air leakage is provided between the variable volume frictional means and the volume type slider.  
     
     
         15 . A washing machine comprising a cabinet having an inner space of a predetermined shape; and a tub positioned in the cabinet and filled with washing water, the washing machine provided with a variable damping type damper, comprising: 
 a cylinder of which one side is provided with a receiving space having a certain depth and another side thereof is coupled to the cabinet or the tub;    a rod of which one side is relative-movably inserted into the receiving space of the cylinder and another side thereof is coupled to the cabinet or the tub;    a guide bar provided at an end portion of the rod;    a variable volume frictional means expanded and contracted in itself by a difference of flow amount introduced/exhausted into/from an inner space by being coupled to the guide bar, and adhered/detached to/from an inner circumferential surface of the receiving space of the cylinder;    a volume type slider performing a relative movement with the variable volume frictional means by being slidably inserted into the guide bar, for causing fluid flow inside the variable volume frictional means; and    a frictional member fixedly coupled to the volume type slider for generating a frictional force with the inner circumferential surface of the receiving space of the cylinder.