Rotary damper

Abstract

A rotary damper includes a housing, a viscous fluid filled in the housing, and a rotor disposed inside the housing and having a shaft part partially protruding from the housing. The rotor has a plurality of rotating resistance parts provided on the shaft part for moving in the viscous fluid inside the housing. A first sloping part is provided on an upstream side of the rotating resistance part to form a distance relative to an inner surface of the housing gradually decreasing toward a downstream side, and a second sloping part is provided on a downstream side of the rotating resistance part to form a distance relative to the inner surface of the housing gradually increasing toward a downstream side.

1 . A rotary damper comprising: 
 a housing,    a viscous fluid filled in the housing,    a rotor disposed in the housing and having a shaft part partially protruding from the housing and a plurality of resistance parts extending radially outwardly from the shaft part for moving in the viscous fluid inside the housing,    a seal member disposed between the shaft part and the housing for preventing leakage of the viscous fluid,    a first sloping part provided on at least one of upper and lower surfaces of the resistance part at an upstream side in a rotational direction thereof and having a distance relative to an inner surface of the housing gradually decreasing toward a downstream side in the rotational direction, and    a second sloping part provided on the at least one of the upper and lower surfaces of the resistance part at the downstream side in the rotational direction and having a distance relative to the inner surface of the housing gradually increasing toward the downstream side in the rotational direction.    
   
   
       2 . A rotary damper according to  claim 1 , wherein said resistance parts are provided on the poles extending radially outwardly from the shaft part.  
   
   
       3 . A rotary damper according to  claim 2 , wherein said first and second sloping parts are formed on the upper and lower surfaces of the poles.  
   
   
       4 . A rotary damper according to  claim 3 , wherein each of said poles has a hexagonal or elliptical cross-sectional shape.  
   
   
       5 . A rotary damper according to  claim 3 , wherein each of said poles has sharp front and read edges forming the first and second sloping parts.  
   
   
       6 . A rotary damper according to  claim 5 , further comprising a circular flat plate arranged coaxially with the shaft part and connecting outer edges of the resistance parts.  
   
   
       7 . A rotary damper according to  claim 1 , wherein each of said resistance parts includes a radial flat portion extending radially outwardly from the shaft part, and an end portion provided on outer side of the radial flat portion and facing upper and lower surface of the housing.  
   
   
       8 . A rotary damper according to  claim 7 , wherein each of said end portion has a diamond shape.  
   
   
       9 . A rotary damper according to  claim 1 , wherein said first sloping part and said second sloping part are provided symmetrically on two sides of the radial flat portions.