Patent Publication Number: US-2003234145-A1

Title: Rotary damper device

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates to a rotary damper device, which can be applied to a rotary device such as a rotary cover or a rotary door opening or closing with a hinge. More particularly, the present invention relates to a damper device preferably applied to a hinge mechanism of a toilet seat/seat lid, which regulates the rotating speed in one direction.  
       [0003] 2. Description of Related Art  
       [0004] A conventional damper device  100  is generally shown in FIGS.  8 ( a ) and  8 ( b ). FIG. 8( a ) shows a cross-sectional view perpendicular to a rotation axis C and FIG. 8( b ) shows a longitudinal sectional view along the rotation axis C.  
       [0005] The damper device  100  is mounted, for example, to a toilet seat hinge of a Western style toilet stool (not shown). In FIG. 8( a ), when the toilet seat/seat lid is moved in an open direction from the closed position, a rotor member  101  rotates in a counterclockwise direction. A check valve  102  attached on the rotor member  101  releases a closed state with a rotation vane  103  due to oil resistance by the rotation of the rotor member  101  in the counterclockwise direction (see right-half section in FIG. 8( a )). Since an orifice  104  formed in the rotation vane  103  is opened so that oil can move with little resistance, the toilet seat/seat lid can be opened with little force.  
       [0006] When the toilet seat/seat lid is moved in a closed direction (clockwise direction in FIG. 8( a )) from the fully opened position, the rotor member  101  rotates with the toilet seat hinge. The movement of the rotor member  101  makes the check valve  102  attached on the rotor member  101  tightly come in contact with the rotation vane  103  of the rotor member  101  due to the oil resistance (see left-half section in FIG. 8( a )). The rotation vane  103  is provided with the orifice  104  and the orifice  104  is closed with the check valve  102 , which is tightly in contact with the rotation vane  103 . The flow of oil is restricted to make the toilet seat/seat lid close slowly by the oil resistance.  
       [0007] The damper device  100  is constituted, as shown in FIG. 8( b ), in such a manner that the rotor member  101  mounted with the check valve  102  is inserted into a case  105 , which is a cylindrical member. The damper device  100  also includes a cover  106  sealed and fixed to the case  105  by screws, supersonic wave welding or the like so as not to leak the oil out after the oil is filled into the case  105 .  
       [0008] However, even though the case  105  and the cover  106  are fixed to each other by screws, supersonic wave welding or the like, the problem of oil leakage is not still solved. That is because the force due to the oil pressure in the case  105  is applied in the direction so as to try to separate the cover  106  from the case  105 .  
       [0009] In addition, when the cover  106  is used, the shaft diameter of the rotor member is restricted by the cover  106 , which gives restrictions on the counterpart member to which the damper device is mounted and thus the scopes and fields of application for the damper device may be limited. Also, when the case is made of metal so as to miniaturize the damper device and also bear the internal-pressure of oil, the supersonic wave welding, which is superior to sealing, can not be used to fix the case  105  and the cover  106  together. Therefore, in this case, it is difficult to obtain the small-sized oil damper device having a strong damping effect.  
       [0010] A damper device in which a rotor shaft is inserted into a case and a screw for fixing the rotor shaft is known in the prior art. However, this is a damper device, in which the back tension of a spring is utilized and the internal-pressure of oil is not generated. A damper device is also known in which an inlet hole for injecting viscous fluid into a case is sealed at the bottom of the case by a bolt after the viscous fluid is injected. However, the damper device is further provided with a cover for preventing oil leakage.  
       SUMMARY OF THE INVENTION  
       [0011] It is an advantage of the present invention to provide a rotary damper device capable of preventing problems due to using a conventional cover for preventing oil leakage.  
       [0012] In order to achieve the above advantage, according to the present invention, there is provided a rotary damper device including a case, a rotor member relatively rotatably supported by the case, a rotation vane formed protruded from the rotor member, and a check valve mounted on the rotation vane. The case is provided with an opened part on one side through which the rotor member is inserted into the inside of the case and a side wall part on the other side for rotatably supporting the rotor member. The opened part of the case is closed by a flange part that is integrally formed in the rotor member.  
       [0013] In accordance with an embodiment of the present invention, the case in which the rotor member is accommodated inside is provided with the side wall part on one side in the axial direction and the rotor member in itself is provided with the flange part on the other side. Therefore, two oil pressure receiving faces are formed by the case in itself and the rotor member in itself and thus a conventional oil leakage preventing cover is not necessary.  
       [0014] Preferably, a seal member is provided on the contacting face of the flange part of the rotor member with the case for assuring the seal of the opened part of the case.  
       [0015] Preferably, a pull-out stopper member is attached to the rotor member interposing the side wall part of the case to prevent the rotor member from pulling out the case easily. When the pull-out stopper member is constituted as a bearing member that serves as a bearing for the rotation shaft of the rotor member, the sliding friction of the rotor member is reduced and thus durability is improved. The pull-out stopper member can be easily attached to the rotation shaft of the rotor member by a screw, caulking, supersonic wave welding, a retaining snap ring or the like.  
       [0016] Preferably, the pull-out stopper member abuts the side surface of the side wall part of the case to assure the function as a pull-out stopper. The case and the rotor member are preferably formed of a metal die-casting to ensure strength.  
       [0017] In accordance with another embodiment of the present invention, there is provided a rotary damper device including a case, a rotor member relatively rotatably supported by the case, a rotation vane formed protruded from the rotor member, and a check valve mounted on the rotation vane. The case is provided at both ends with enlarged inner wall face parts that are respectively opened and formed in a larger diameter than a middle portion. A flange part of the rotor member and a bearing member are respectively fitted tightly to the enlarged inner wall face parts in a freely sliding manner at both ends of the case. Both of the side faces of the flange part and the bearing member are formed as oil pressure receiving faces in the rotor shaft direction.  
       [0018] In this constitution, the flange part of the rotor member and the bearing member are formed as oil pressure receiving faces in the axial direction. Therefore, a conventional oil leakage preventing cover is not used. Moreover, since the bearing member fixed to the rotor member is fixed to a rotation shaft of the rotor member, the bearing member can be firmly attached to the rotor member.  
       [0019] Preferably, the case and the rotor member are formed of a metal die-casting to ensure strength. Seal members are preferably used between the case and the rotor member and between the case and the bearing member to improve seal property. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0020] FIGS.  1 ( a ) and  1 ( b ) show cross-sectional views of a damper device in accordance with a first embodiment of the present invention, wherein FIG. 1( a ) shows a cross-sectional view along a rotation shaft and FIG. 1( b ) shows a cross-sectional view taken on line B-B in FIG. 1( a ).  
     [0021]FIG. 2 shows a cross-sectional view of a damper device along a rotation shaft in accordance with a second embodiment of the present invention.  
     [0022]FIG. 3 shows a cross-sectional view of a damper device along a rotation shaft in accordance with a third embodiment of the present invention.  
     [0023]FIG. 4 shows a cross-sectional view of a damper device along a rotation shaft in accordance with a fourth embodiment of the present invention.  
     [0024]FIG. 5 shows a cross-sectional view of a damper device along a rotation shaft in accordance with a fifth embodiment of the present invention.  
     [0025] FIGS.  6 ( a ) and  6 ( b ) show an operational explanatory view of a check valve in a braking state in the damper device of the present invention.  
     [0026] FIGS.  7 ( a ) and  7 ( b ) show an operational explanatory view of a check valve in a slipping state in the damper device of the present invention.  
     [0027] FIGS.  8 ( a ) and  8 ( b ) show an operational explanatory view in a conventional damper device.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0028] Damper devices in accordance with embodiments of the present invention are described below with reference to the accompanying drawings. FIGS.  1 ( a ) and  1 ( b ) show cross-sectional views of a damper device in accordance with a first embodiment of the present invention. FIG. 1( a ) shows a cross-sectional view along a rotation shaft and FIG. 1( b ) shows a cross-sectional view taken on line B-B in FIG. 1( a ), which shows a general constitution of a check valve  30 .  
     [0029] A damper device  10  in accordance with a first embodiment of the present invention is provided with a fixing portion  12  for fixing the damper device  10  to a Western style toilet stool that is not illustrated. The fixing portion  12  is integrally formed with a case  14 . The fixing portion  12  is provided with a hole  12   a  for passing a bolt through and a counterbore hole  12   b  for accommodating the head part of the bolt. The case  14  is so constituted, as shown in FIG. 1( a ), that one side (downside in the drawing) forms an opened part for allowing a rotation shaft  20  protruding outside. The external peripheral part on the other side (upside in the drawing) of the case  14  is formed as a fixed shaft part  14   a,  which is integrally formed with the case  14 .  
     [0030] For the use in a toilet seat/seat lid, a pair of damper devices  10  are used at right and left positions in a Western style toilet stool. The viscosities of the oils used in the damper devices  10  are respectively changed to obtain different damping effects. For example, one of the damper devices  10  having less damping effect is mounted to a seat lid (not shown) in such a manner that the protruding part  20 A of the rotation shaft  20  is fixed to the seat lid. A toilet seat (not shown) which has a larger weight than the seat lid is rotatably supported on the fixed shaft part  14 a of the case  14 . The other of the damper devices  10  having larger damping effect is mounted to the toilet seat in such a manner that the protruding part  20 A of a rotation shaft  20  is fixed to the toilet seat. The lightweight seat lid is rotatably supported on the fixed shaft part  14   a  of the case  14  in the other damper device  10 .  
     [0031] As shown in FIG. 1( b ), two partition parts  16  are radially protruded toward a center direction in an axial symmetrical manner at two positions on the cylindrical inner wall surface  14   b  of the case  14 . The tip end of the partition part  16  is formed in an arc face so as to fit loosely on the outer peripheral face of the rotation shaft  20 , which constitutes a rotor member  18 . Rotation vane parts  22  are formed on the rotor member  18  in an axial symmetrical manner so as to protrude from the rotation shaft  20  toward the cylindrical inner wall surface  14   b.  The tip end of the rotation vane part  22  is formed in an arc face along the cylindrical inner wall surface  14   b.  The rotation vane part  22  is constituted so as to be interposed by two oil pressure receiving faces  24   a  and  24   b  in an axial direction of the rotor member  18 . The oil pressure receiving face  24   a  is the inner side face of a flange part  25  that is integrally formed in the rotation shaft  20  of the rotor member  18 . Two O-rings  25   a  for sealing are dually attached on the outer peripheral face of the flange part  25  so as to press and come into contact with the cylindrical inner wall surface  14   b  of the case  14 . The other oil pressure receiving face  24   b  is an inner side face formed by the case  14 , that is, the inner side face of a side wall part  27  provided with a through-hole  26  for rotatably supporting the rotation shaft  20 . An O-ring  26   a  for seal is attached on the inner peripheral part of the side wall part  27  in such a manner that the O-ring  26   a  tightly contacts with the rotation shaft  20 .  
     [0032]FIG. 2 shows a cross-sectional view of a damper device in accordance with a second embodiment of the present invention. The constitution and the operation of the fixing portion  12  and the check valve  30  are similar to those of the first embodiment shown in FIG. 1. The same numerical code in the drawing as in FIG. 1 refers to the same member as the first embodiment and its description is omitted. A damper device  40  in the second embodiment differs from the first embodiment in that a flange part  25 - 2  constitutes the rotor member  18 - 2 , and other elements are similar to the first embodiment. In the first embodiment, two O-rings for sealing are used on the outer periphery of the flange part  25  in parallel so as to deal with oil of low viscosity, but only one O-ring for sealing is used as shown in the flange part  25 - 2  in the second embodiment.  
     [0033] In accordance with the damper device of the present invention, a conventional oil leakage preventing cover is not used due to the above described constitution. Therefore, an external connecting part  21  of the rotation shaft, which constitutes the rotor member  18 - 2 , is not necessary to make a smaller diameter in order to attach the oil leakage preventing cover. In the damper device  40  of the second embodiment, the external connecting part  21  of the rotor member  18 - 2 , which is integrally formed with the rotation shaft  20 - 2  together, can change its radial dimension and shape freely. In other words, the outside diameter of the external connecting part  21  can be formed larger than that of the casing  14 .  
     [0034]FIG. 3 is a cross-sectional view of a damper device in accordance with a third embodiment of the present invention. A damper device  50  of the third embodiment is an example in which a screw member  34  mounting a bearing plate  32  to a rotor member  18 - 2  shown in FIG. 2 is replaced by a caulking part. The bearing plate  32  serves as a pull-out stopper member for the rotor member  18 - 2 . A smaller diameter part  20   a  of the rotation shaft  20  passing through the through-hole  26  of the side wall part  27  is extended longer. An O-ring  20   d  is mounted around a smaller diameter part  20   a - 3  instead of an O-ring  26   a  mounted on the inner peripheral face of the side wall part  27 .  
     [0035] A fitting portion of the smaller diameter part  20   a - 3  for a bearing plate  32 - 3  is formed in an elliptic or polygonal cross-sectional shape so that the bearing plate  32 - 3  rotates with the smaller diameter part  20   a - 3  together. The bearing plate  32 - 3  is formed in a thin disk shape and not provided with an O-ring  32   a  in FIG. 2. A fitting hole is provided in the bearing plate  32 - 3  to engage with the smaller diameter part  20   a - 3  in the circumferential direction so that the bearing plate  32 - 3  rotates with the smaller diameter part  20   a - 3  together. The protruded part of the smaller diameter part  20   a - 3  from the bearing plate  32 - 3  is plastically deformed to form a caulking part  20   c.  This caulking part  20   c  and the bearing plate  32 - 3  prevent a rotor member  18 - 3  from being pulled out the case  14 . In this case, the bearing plate  32 - 3  serves as a pull-out stopper member for the rotor member  18 - 3 . The operation and usage of the damper device  50  in the third embodiment are similar to those of the damper device  10  in the first embodiment.  
     [0036]FIG. 4 shows a cross-sectional view of a damper device in accordance with a fourth embodiment of the present invention. The damper device  60  of the fourth embodiment uses a retaining snap ring  35  instead of the caulking part  20   c  in FIG. 3. The inner diameter portion of the retaining snap ring  35  is formed smaller than the outer diameter of a smaller diameter part  20   a - 4  of a rotation shaft. Therefore, the retaining snap ring  35  is pushed and fitted on the smaller diameter part  20   a - 4  from the left side and prevented from a backward movement because of its elastically deformed inner diameter portion. The structure of a bearing plate  32 - 4  and the smaller diameter part  20   a - 4  may be similar to those of the damper device  50  in the third embodiment.  
     [0037]FIG. 5 shows a cross sectional view of a damper device in accordance with a fifth embodiment of the present invention. The damper device  70  of the fifth embodiment is an example which is not provided with the side wall part  27  of the case  14 . The case  14  is provided at both ends with enlarged inner wall face parts  14   d  which are respectively formed opened parts in a larger diameter than the middle portion of the case  14 . A flange part  25 - 5  of a rotor member  18 - 5  and a bearing plate  32 - 5  are respectively fitted to the enlarged inner wall face parts  14   d  in a freely sliding manner at both ends of the case  14 . An O-ring  25   a  is mounted around the flange part  25 - 5  of a rotor member  18 - 5  and an O-ring  32   b  is mounted around the bearing plate  32 - 5 . The opposing side faces of the flange part  25 - 5  and the bearing plate  32 - 5  are formed as oil pressure receiving faces  24   a  and  24   b  in the rotation shaft direction.  
     [0038] A smaller diameter part  20   a - 5  is formed at the left end side of a rotation shaft  20 - 5  of a rotor member  18 - 5  and the bearing plate  32 - 5  having a fitting hole  36  is fitted to the end portion of the smaller diameter part  20   a - 5 . The fitting hole  36  of the bearing plate  32 - 5  is concavely formed with a depth of greater than half of the thickness of the bearing plate  32 - 5  in the axial direction. The smaller diameter part  20   a - 5  of the rotation shaft  20 - 5  is fitted into the fitting hole  36  and the outer peripheral face of the smaller diameter part  20   a - 5  is sealed with an O-ring  20   e  The bearing plate  32 - 5  is fixed to the rotation shaft  20 - 5  with a screw member  34  to rotate in an internal manner. The screw member  34  is preferably locked by an adhesive agent or the like. The bearing plate  32 - 5  and the flange part  25 - 5  are respectively abutted against enlarged step parts  14   e  provided on both sides of the case  14  in a sliding manner in a circumferential direction and the movement of the rotor member  18 - 5  is restricted in the axial direction. The bearing plate  32 - 5  and the flange part  25 - 5  respectively form the oil pressure receiving faces  24   a  and  24   b.    
     [0039] Next, the operation of the damper device of the present embodiment is described below with the reference to FIGS.  6 ( a ) and  6 ( b ). In FIG. 6, both side faces  22   a  on the tip side of each rotation vane  22  in the axial direction are opposed to the oil pressure receiving faces  24   a  and  24   b  with a gap “s”. The thickness of each rotation vane  22  in a rotational direction is set in such a manner that the central part is formed thinner than the protruded part  22   b  formed at both sides in the axial direction. A cutout part  29  with a prescribed axial length and depth is formed as an orifice in the central part where its thickness is made thinner.  
     [0040] The check valve  30  is a rectangular tube body which is interposed in the gap “s” between the side faces  22   a  of the rotation vane  22  and the oil pressure receiving faces  24   a  and  24   b  so as to surround the rotation vane  22 . The outer tip end surface, which slides with the cylindrical inner wall surface  14   b,  is formed in a circular face. The check valve  30  is provided with a closing part  30   a  that is capable of closing the entire cutout part  29  (orifice) formed in the rotation vane  22 . The check valve  30  is also provided with a connecting part  30   b  which is formed so as to connect both sides of the closing part  30   a  in the axial direction on the opposite side across the rotation vane  22 . When the rotation vane  22  is rotated in the CCW direction in FIG. 6( a ), the closing part  30   a  closes the entire cutout part  29  (orifice) of the rotation vane  22  to perform a damper function. The connecting part  30   b  is formed about half the radial length from the base portion to the outer tip end of the rotation vane  22 . The dosing part  30   a  and the connecting part  30   b  of the check valve  30  are fitted to the rotation vane  22  so as to have a gap “p” in the rotational direction. Thus the check valve  30  is supported by the rotation vane  22  so as to be able to move within the gap “p” along the cylindrical inner wall surface  14   b.    
     [0041] Next, the assembling method of the damper device  10  is described below with the reference to FIGS.  7 ( a ) and  7 ( b ). In FIG. 7( a ), a specified amount of silicone oil  31  (hereinafter, referred to as oil) is filled in the case  14 . Then, the check valve  30  is mounted on the rotation vane  22  and the rotor member  18  having the flange part  25 , on which the O-ring  25   a  is attached on the outer peripheral face, is inserted into the case  14 . The tip end of the smaller diameter part  20   a  of the rotation shaft  20  is inserted through the through-hole  26  of the side wall part  27  of the case  14 . And then a smaller diameter step part  20   b  of the rotation vane  22  is positioned to be close to the inner surface of the side wall part  27  in a sliding state in the rotational direction.  
     [0042] In the case of the embodiment in FIG. 2, the O-ring  26   a  is mounted on the through-hole  26  of the side wall part  27  of the case  14  from the side opposite to the inserting direction of the rotor member  18 - 2 . Then, the bearing plate  32  mounting the O-ring  32   a  on its outer periphery is inserted into the case  14 , fastened to the rotation shaft  20 - 2  with a screw member  34  such as a bolt, and locked by using adhesive such as a screw lock agent. The O-ring  25   a  is fitted around the flange part  25 - 2 , which is formed integrally with the rotor member  18 - 2  so as to contact sidably with the opened part, that is, the cylindrical inner wall surface  14   c  of the case  14 . The flange part  25 - 2  is positioned on the outer side from the partition part  16  projected from the cylindrical inner wall surface  14   b  of the case  14  in the axial direction. The inner side surface  25   b  of the flange part  25 - 2  is sidably in contact with the side surface of the partition part  16 . The rotation shaft  20 - 2  and the bearing plate  32  are constituted as one body and the rotor member  18 - 2  is supported by the case  14  to be rotated relatively.  
     [0043] In FIGS. 6 and 7, the silicone oil  31  is filled inside the case  14  and sealed up between the oil pressure receiving face  24   a  of the flange part  25  and the oil pressure receiving face  24   b  of the side wall part  27  in the direction of the rotor shaft. It is important that the oil pressure receiving face  24   a  is formed by the flange part  25  formed integrally with the rotor member  18  and the oil pressure receiving face  24   b  is formed by the side wall part  27  formed integrally with the case  14 . Two partial cylindrical rooms  33 , which are arcuately formed between the two partition parts  16  of the case  14 , are respectively divided into an oil chamber  33   a  and an oil chamber  33   b  by the rotation vane  22 . When the check valve  30  is fitted to the rotation vane  22 , a simple stopper member such as a snap fitting is preferably used to prevent the check valve  30  from falling off the rotation vane  22  to improve assembling workability. By the above-mentioned constitution, an oil leakage preventing cover is not necessary in the damper device of the present invention.  
     [0044] Next, the operation of the damper device according to the present invention is described below. FIGS.  6 ( a ) and  6 ( b ) show an operational explanatory view of the check valve  30  in a braking state, when the rotation vane  22  moves in the working direction (CCW direction in the drawing) of the damper function. FIGS.  7 ( a ) and  7 ( b ) show an operational explanatory view of the check valve  30  in a slipping state, when the rotation vane  22  moves in the slipping direction (CW direction in the drawing) so that the damper function is not operated. FIGS.  6 ( a ) and  7 ( a ) each shows a cross-sectional view perpendicular to the rotation shaft, and FIGS.  6 ( b ) and  7 ( b ) each shows a cross-sectional view along the rotation shaft.  
     [0045] In FIGS.  6 ( a ) and  6 ( b ), when the rotation shaft  20  is rotated in the counter-clockwise direction CCW with respect to the case  14 , the oil in the oil chamber  33   a  is pressurized and tries to move to the oil chamber  33   b.  Thus, the check valve  30  is tightly in contact with the rotation vane  22  by the oil pressure and closes the cutout part  29  of the rotation vane  22 . Accordingly, the oil  31  moves only through the gaps between the inner wall face of the case  14  and the rotation shaft  20 , the rotation vane  22 , the check valve  30  or the like. The oil resistance in this state gives a braking force and thus a toilet seat/seat lid can be closed slowly.  
     [0046] In FIGS.  7 ( a ) and  7 ( b ), when the rotation shaft  20  is rotated in the clockwise direction CW with respect to the case  14 , the oil in the oil chamber  33   b  is pressurized and tries to move to the oil chamber  33   a.  At this time, the check valve  30 , for example, at a position shown in FIGS.  6 ( a ) and  6 ( b ) moved by the gap “p” to open the cutout part  29  by the oil pressure. Accordingly, as shown in FIG. 7( a ), the gap “p” between the rotation vane  22  and the check valve  30  and the cutout part  29  form an oil passage  33 c. The oil  31  can easily move from the oil chamber  33   b  to the oil chamber  33   a  through the oil passage  33   c  when the rotation shaft  20  is rotated in the clockwise direction. Therefore, since a large oil resistance is not generated, the rotation shaft  20  is rotated easily and the toilet seat/seat lid can be opened with little force.  
     [0047] 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.  
     [0048] For example, the damper device according to the present invention 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.  
     [0049] As described above, the rotary damper device according to the present invention is not needed to use a conventional oil leakage preventing cover. Accordingly, necessary parts are reduced, assembling of the device becomes easy and cost can be reduced. Unexpected expansion of the oil passage within the case by the internal-pressure of oil can be reduced. Further, the shaft part of the rotor member can be formed larger than the case and thus a wide range of applications can be obtained.  
     [0050] While the description above refers to particular embodiments of the present 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.  
     [0051] 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.