Abstract:
A rotary damper device includes a case in which a viscous fluid is filled and sealed, a rotation shaft relatively rotatably supported by the case, a rotation vane formed protruded from the rotation shaft, and a check valve mounted on a tip part of the rotation vane. A passage where the viscous fluid passes through is formed in the rotation vane. The check valve is provided with an opposing face part facing the passage and a frame body interposing the rotation vane. An elastic member for energizing the opposing face part of the check valve for closing the passage of the rotation vane is formed in either the rotation vane or the opposite side of the frame body of the opposing face part.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a rotary damper device, and more particularly to a rotary damper device that is used in a rotational cover or a rotational door. 
     2. Description of the Related Art 
     A conventional rotary damper device is generally constituted in such a manner that a rotor shaft mounted with a check valve is enclosed in a case in which oil is filled, and a cover is tightly fitted and fixed to the case by screws, supersonic wave welding or the like. Such a rotary oil damper device is used not only in a rotational cover or a rotational door but also as a damper device regulating the rotating or swinging speed of a toilet seat and/or a seat lid. When the toilet seat/seat lid with the damper device is moved in a closing direction from an opened state, a rotor shaft rotates with the toilet seat to make a check valve mounted to the rotor shaft tightly contact with a vane of the rotor shaft. The vane is provided with an orifice, which is closed by the check valve abutting against the vane to restrict the flow of oil, and thus, the toilet seat/seat lid is slowly closed. 
     When the toilet seat/seat lid is moved in an open direction from the closed state, the rotor shaft is rotated or swung, and the check valve attached to the rotor shaft is released from the contacting state with the vane. As a result, the orifice formed in the vane is opened so that the oil can move without resistance and the toilet seat/seat lid can be easily opened. 
     However, check valves in the prior-art have various problems that need to be solved. For example, a conventional check valve is formed substantially U-shaped and is movable until the right or left butting part of the check valve abuts against the vane. In this type of check valve, since the check valve can move in either direction by oil resistance as the rotor shaft moves, it requires some time for the check valve to close the orifice of the vane. This period causes a slip angle that does not work as a damper function for the rotor shaft. In the case of the slip angle being large, when a toilet seat is opened halfway and released, the toilet seat may collide with the toilet stool bowl. Also, the large slip angle causes variations in angle when the toilet seat is braked. 
     A damper device without a backlash, is complicated and requires a lot of components. Also, a rotary damper is a damper in which the slip angle is reduced by using a spring, hut many components are required and its assembling workability is not satisfactory. 
     A device in which a viscous fluid pressure receiving part is provided with elasticity is also known in the prior art. However, with this device, the elastic deformation part is formed in the portion to which a high pressure of viscous fluid is applied causes a problem of its durability. 
     SUMMARY OF THE INVENTION 
     It is an advantage of the present invention to provide a rotary damper device capable of preventing a slip angle (backlash) and quickly operating a braking or damper function with a simple constitution at a low cost. 
     In accordance with an embodiment of the present invention, a damper device may include a case in which a viscous fluid is filled and sealed, a rotation shaft rotatably supported by the case, a rotation vane formed protruded from the rotation shaft and a check valve mounted on the tip part of the rotation vane, wherein a passage where the viscous fluid passes through is formed in the rotation vane, the check valve is provided with an opposing face part facing the passage and a frame body interposing the rotation vane, and an elastic member for energizing so that the opposing face part of the check valve closes the passage of the rotation vane formed in either of the rotation vane or the opposite bide of the frame body of the opposing face part. 
     As a result, with a simple constitution, when the rotation shaft is rotated in a damper operating direction, the opposing face part of the check valve closes the passage of the fluid in the rotation vane and, when the rotation shaft is turned in the opposite direction, in other words, in a slipping direction, the opposing face part of the check valve opens the passage of the fluid by the flowing pressure of the viscous fluid. 
     In the present invention, when the elastic member is integrally formed with the frame body of the check valve opposite the opposing face part so as to abut the rotation vane, the constitution can be further simplified. 
     Preferably, the elastic member is integrally formed with the frame body by using a synthetic resin with oil resistance and wear resistance, and may be formed in a feeler shape, a T-shape, an arch-shape, a truncated chevron shape, or the like. 
     Preferably, a regulating part is formed between the rotation vane and the opposite side of the frame body to the opposing face part for restricting the amount of elastic deformation of the elastic member. When the regulating part is provided, the elastic member is elastically doformed within the predetermined range of elasticity and thus a stable operation can be performed for a long period. 
     The regulating part may be formed by protruding from the rotation vane or by protruding from the frame body. Also, when the regulating part is constituted of two protrusion parts and the elastic member is formed between them, the elastic member can be protected with the two protrusion parts and thus a reliable operation can be attained with a simple construction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of a damper device in accordance with one embodiment of the present invention. 
         FIG. 2  shows an exploded perspective view of the damper device shown in FIG.  1 . 
         FIG. 3  shows operation explanatory views of a check valve at a braking time in the damper device shown in  FIG. 1 , wherein FIG.  3 ( a ) shows a cross-sectional view perpendicular to the shaft and FIG.  3 ( b ) shows a longitudinal sectional view along the shaft. 
         FIG. 4  shows operation explanatory views of the check valve at a slipping time in the damper device shown in  FIG. 1 , wherein FIG.  4 ( a ) shows a cross-sectional view perpendicular to the shaft and FIG.  4 ( b ) shows a longitudinal sectional view along the shaft. 
         FIG. 5  shows perspective views of check valves each of which is integrally formed with an elastic member in accordance with other embodiments of the present invention, wherein FIG.  5 ( a ) shows a T-shaped elastic member, FIG.  5 ( b ), an arch-shaped elastic member and FIG.  5 ( c ), two bar-shaped elastic member. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A damper device in accordance with one embodiment of the present invention is described below with reference to the accompanying drawings.  FIG. 1  shows a perspective view of a damper device in accordance with one embodiment of the present invention and  FIG. 2  shows an exploded perspective view of the damper device shown in FIG.  1 . 
     A reference number  10  shows a damper device. The damper device  10  is constituted in such a manner that an O-ring  16  is fitted in an annular groove  14  formed on a rotation shaft  12  (see FIG.  3 ). A check valve  20  is respectively held on a tip part of two rotation vanes  18  symmetrically projected in a radial direction and inserted into inside a case  22  having a bottom, and a specified amount of silicone oil as a viscous fluid is filled within the case  22 . Partition parts  23  located symmetrically apart 180 degrees each other are projected toward the center direction from the cylindrical inner wall surface  22   a  of the case  22 . The height of the partition part  23  is determined so that the inner end of the partition parts  23  sides roughly on the outer surface of the rotation shaft  12 . The space formed by the partition parts  23  is divided into two chambers of a pressure applied oil chamber  24   a  and a pressure reduced oil chamber  24   b  by the rotation vane  18 . 
     A cover  25  is fixed to enclose the case  22  by screws  26  to prevent the oil from leaking. Sealing and fixing can be performed by ultrasonic wave adhesion when the case  22  is formed of a synthetic resin. When the check valve  20  is mounted to the rotation shaft  12 , providing a simple slip-off preventing part such as a snap fitting may preferably prevent the check valve  20  from falling off the rotation vane  18 , which improves assembling workability. The check valve  20  is integrally formed with a pair of elastic protrusion parts  30 - 1  as an elastic member for energizing the check valve  20  in such a direction that an oil passage  28  formed in the rotation vane  18  is closed. 
     The oil passage  28  is a notch part formed concavely at the outer peripheral side of the central portion of the rotation vane  18 , which is formed like a flat plate-shape in an axial direction. The check valve  20  is provided with an opposing face part  20   a  for closing the oil passage  28 , and with a frame body  20   b  formed to interpose and surround the tip part of the rotation vane  18 . A frame connecting part  20   b - 1  connecting both end parts of the frame body  20   b  in the axial direction of the rotation shaft  12  is formed on the opposite side to the opposing face part  20   a . The elastic protrusion parts  30 - 1  are formed on the fame connecting part  20   b - 1 , which serves also to prevent the check valve  20  from falling off the rotation vane  18 . 
     The elastic protrusion parts  30 - 1  are formed in a V-shaped leg section  31 - 1  as a first embodiment and so constituted that the end parts are abutted and pushed against the wall face of the rotation vane  18  even at a stopping state. Therefore, at a stopping state when a rotating operation is not executed, the frame connecting part  20   b - 1  is positioned apart from the rotation vane  18  by the elastic force of the elastic protrusion parts  30 - 1 . As a result, the opposing face part  20   a  of the check valve  20  is positioned to close the oil passage  28 . On the contrary, even though the opposing face part  20   a  does not completely dose the oil passage  28  at a stopping state, the operation can be satisfactorily performed because the slip angle is extremely reduced. In other words, at a stopping state, it is not necessary for the tip ends of the elastic protrusion parts  30 - 1  to press the wall face of the rotation vane  18 . The tip ends of the elastic protrusion parts  30 - 1  may be constituted so as to only contact with or be apart from the wall face of the rotation vane  18  with a little gap. 
     The elastic protrusion parts  30 - 1  are protected from outside by the frame body  20   b  of the check valve  20 , which is formed surrounding the periphery of the elastic protrusion parts  30 - 1 , and thus external forces more than the elastic limit are not applied to them. 
     Regulating protrusion parts formed protruding to the frame body side, where the elastic protrusion parts  30 - 1  are provided, are formed at both end parts of the rotation vane  18  in the axial direction. When the check valve  20  is located at a position where the check valve  20  does not close the oil passage  28  by the oil flowing pressure as shown in  FIG. 4 , the regulating protrusion parts  18 - 1  keep a gap or some predetermined space between the rotation vane  18  and the frame body  20   b  where the elastic protrusion parts  30 - 1  are formed. This gap prevents the elastic protrusion parts  30 - 1  from being unnecessarily deformed by the rotation vane  18 . Therefore, since the fatigue due to the repetitive operation of the elastic protrusion parts  30 - 1  is reduced, the damage of the elastic protrusion parts  30 - 1  is prevented and useful life can be improved. Furthermore, the maximum stress is applied to the elastic protrusion parts  30 - 1  only at the time of the rotation shaft  12  and the rotation vane  18  rotating in the slipping and not-braking direction. Accordingly, the act of resin creep due to high temperature is extremely reduced even when the elastic protrusion parts  30 - 1  are formed of a resin molding. 
     In the above-mentioned embodiment, the regulating protrusion parts  18 - 1  are formed protruded from the rotation vane  18 . However, the regulating protrusion parts  18 - 1  may be formed protruded from the frame body  20   b  or the frame connecting part  20   b - 1 . The elastic protrusion parts  30 - 1  may be formed on the rotation vane  18  and the frame connecting part  20   b - 1  may be abutted with the elastic protrusion parts. 
     Next, the operation of the damper device in the present invention is described below with the reference to  FIGS. 3 and 4 .  FIG. 3  a shows explanatory views of the damper device at a braking operation, wherein FIG.  3 ( a ) shows a cross-sectional view perpendicular to the shaft and FIG.  3 ( b ) shows a longitudinal sectional view along the shaft.  FIG. 4  shows explanatory views of the damper device at a slipping operation, i.e., at a not-braking operation, wherein FIG.  4 ( a ) shows a cross-sectional view perpendicular to the shaft and FIG.  4 ( b ) shows a longitudinal sectional view along the shaft. 
     In FIG.  3 ( a ), when the case  22  is fixed and the rotation shaft  12  is rotated in a CCW direction in the figure, the oil of the oil chamber  24   a  is pressurized to move to the oil chamber  24   b . However, the opposing face put  20   a  of the check valve  20  abuts with the rotation vane  18  by the oil pressure and closes the oil passage  28 . Therefore, the oil moves only through the gap formed between the cylindrical inner wall surface  22   a  of the case  22  and the outer periphery face of the check valve  20  and through the gap formed between the rotation shaft  12  and the case  22 . Accordingly, the braking-force, i.e., damping-force is produced by flowing resistance of the oil and the toilet seat/seat lid (not shown) are slowly closed against their own weight. 
     When the rotation shaft  12  is turned in a CW direction in FIG.  4 ( a ), the oil of the oil chamber  24   b  is pressurized to move to the oil chamber  24   a . The feeler-shaped elastic protrusion part  30 - 1 , which is the first embodiment of the elastic member, formed on the opposite side of the opposing face part  20   a  are elastically bent by the oil pressure. That is, the V-shaped leg section  31 - 1  is elastically bent and the check valve  20  is moved to the oil chamber  24   a  side. Consequently, the opposing face part  20   a  of the check valve  20  is allowed to move apart from the rotation vane  18  to open the oil passage  28  and the oil can flow through the oil passage  28 . 
     As described above, the rotation of the rotation shaft  12  is swiftly performed in a slipping direction where the damper effect is not generated because the oil can flow from the oil chamber  24   b  to the oil chamber  24   a  without much resistance through the oil passage  28 . Therefore, the toilet seat/seat lid can be lightly opened with a little force. When the rotation of the rotation shaft  12  is stopped, the opposing face part  20   a  of the check valve  20  is brought to closely contact with the rotation vane  18  by the energized force of the elastic protrusion parts  30 - 1 , which is integrally formed in the check valve  20 . This means that the slip angle (backlash) is extremely reduced at the time of the rotation in the opposite direction where the damper action is required. Consequently, the damper effect can be generated at once just after the beginning of the rotation in the opposite direction and the safety of the toilet seat/seat lid can be improved. 
     When the check valve  30  is constituted by molding of synthetic rain, the shape of the elastic protrusion parts  30 - 1  projected on the inner surface at the opposite side from the opposing face part  20   a  can be easily formed like a V-shaped leg section  31 - 1  on the frame connecting part  20   b - 1 . The elastic energized force of the elastic protrusion parts  30 - 1  is necessary to be set weaker than the flowing pressure of the oil in the slipping direction. 
     Alternative examples of the elastic protrusion parts  30 - 1  are shown in FIG.  5 . FIG.  5 ( a ) shows a second embodiment in which an elastic protrusion part  30 - 2  is formed in a T-shape instead of the V-shaped leg section  31 - 1 . The frame connecting part  20   b - 1  connecting both end parts of the frame body  20   b  is formed on the opposite side to the opposing face part  20   a . The T-shaped elastic protrusion part  30 - 2  is formed by integral molding in such a manner that two arms  31 - 2  are horizontally extended on the right and left sides from the center of the frame part  20   b - 1 . When the rotation vane  18  is moved in the slipping direction, the rotation vane  18  abuts against the tip ends of the arms  31 - 2  to cause the elastic deformation of the arms  31 - 2  by the flowing pressure of the oil for allowing the fluid to flow through the oil passage  28 . 
     FIG.  5 ( b ) shows a third embodiment in which an elastic protrusion part  30 - 3  is formed in an arch-shape. The oil passage  28  formed on the tip portion of the rotation vane  18  is formed as an opening hole, which is different from the notch in the above-mentioned embodiment. The upper part above the opening hole of the rotation vane  18  abuts against the tip end of the arch part  31 - 3  of the elastic protrusion part  30 - 3  which causes the elastic deformation of the arch part  31 - 3 . In other words, the arch part  31 - 3  bends a little in a somewhat flat shape. 
     FIG.  5 ( c ) shows a fourth embodiment in which an elastic protrusion part  30 - 4  is formed in a two-bar shape, i.e., in a truncated chevron shape. The elastic protrusion part  30 - 4  is formed so as to oppose the rotation vane  18  as the third embodiment, small protrusions  31 - 4  in the truncated chevron shape are brought into contact with the upper part above the opening part of the rotation vane  18 , 
     As described above, the damper device according to the present invention is provided with the check valve mounted on the rotation vane, on which a small elastic protrusion part is formed. Therefore, the slip angle (backlash) of the damper device can be reduced without increasing component when the rotating direction is changed from the slipping direction to the braking direction. As a result, even when the toilet seat/seat lid is released at the time of being opened halfway, the toilet seat/seat lid is prevented from dropping and crashing against the toilet stool bowl because a damper function and a braking operation are effectively and quickly performed 
     Such a damper device can be effectively used not only in a toilet seat/seat lid but also in a moving body such as a door closer or the lid of a trash box, which is connected by a hinge to swing lightly in one direction and slowly in the opposite direction. 
     The embodiments of the present invention are described above. However, needless to say, the present invention is not limited to the embodiments described above, and many modifications can be made without departing from the subject matter of the present invention. 
     For example, the shock valve  20  is preferably mounted in the tip part of the rotation vane  18  in consideration of its assembling efficiency. However, the check valve  20  may be mounted in the partition part  23  projected inside from the case  22  in a radial direction to expect the similar effect. Also, either of the rotation shaft  12  or the case  22  may be rotated. 
     As described above, a damper device is provided with a check valve arranged at a passage for a viscous fluid and an elastic member substantially energizing the check valve on a surface for braking the rotational speed of the rotation vane even at a time of stopping. As a result, a braking or damper action is executed almost without producing a slipping angle by backlash. 
     In the damper device described above, when the elastic member is integrally formed with the check valve by using synthetic resin with oil resistance and abrasion resistance, necessary components are reduced and assembling can be improved at a low cost. 
     Further, in the damper device according to the present invention, the check valve is constituted so as to interpose both side faces of the rotation vane, and the elastic member is formed between the rotation vane and inside the frame body of the check valve for restricting the rotational speed of the rotation vane. Therefore, the elastic member can be deformed within a limited range without receiving high pressure. 
     While the description above refers to particular embodiments of the invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention. 
     The disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive. The scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.