Rotary damper

Abstract

The present invention can easily adjust the damping torque caused by rotation with a simple structure. A rotary damper (1) is used to restrict the movement of a viscous fluid filled in a cylindrical chamber (111), thereby generating a damping torque in response to an applied rotational force. The cover (15) is of a screw-fitting type that can be screw-fitted to the housing (11). By changing the screw-fitting amount of the cover (15) and the housing (11), the gap G1 between the cover (15) and each partition portion (115) is adjusted, thereby adjusting the amount of the viscous fluid moving through the gap G1, and thus adjusting the damping torque caused by rotation. Each axial force generating member (17) includes an element that can be plastically or elastically deformed, and is located between the cover (15) and the corresponding partition portion (115) so as to apply a reaction force to the cover (15). Thus, an axial force is generated by screw-fitting the cover (15) to the housing (11), preventing the viscous fluid from leaking outward through the threaded joint portion between the cover (15) and the housing (11), and increasing the adjustment margin for the gap G1.

Description

Technical Field

[0001] The present invention relates to a rotary damper, and more particularly to a rotary damper having an adjustable damping torque caused by rotation. Background Art

[0002] A damper is known that generates a large damping torque for forward rotation and a small damping torque for reverse rotation. For example, Patent Document 1 discloses a rotary damper that has a simple structure and can be manufactured at low cost.

[0003] The rotary damper disclosed in Patent Document 1 has: a housing including a cylindrical chamber defined therein; a rotor rotatably disposed in the cylindrical chamber; a viscous fluid filled in the cylindrical chamber; and a lid mounted on an open end of the housing to hold the rotor and the viscous fluid together and seal them in the cylindrical chamber.

[0004] The rotor includes a cylindrical rotor body and blades each formed to project radially outward from an outer peripheral surface of the rotor body so as to form a minute gap with a side wall surface in the cylindrical chamber. Each blade has a flow path leading to both side surfaces perpendicular to the rotation direction of the rotor: one side surface (referred to herein as the first side surface) and the other side surface (referred to herein as the second side surface) of the blade. A sealing member is mounted on an end surface (the surface facing the side wall surface in the cylindrical chamber) of each blade, thereby filling the minute gap between the end surface and the side wall surface in the cylindrical chamber. These sealing members each have an elastic check valve for opening and closing the flow path formed in the corresponding blade. The side wall surface in the cylindrical chamber has spaced portions each formed to project radially inward to form a gap with the outer peripheral surface of the rotor body.

[0005] According to the above structure, in the rotary damper disclosed in Patent Document 1, if a force is applied to the rotor to rotate the rotor in the direction from the first side surface of each blade to the second side surface (in the forward direction), the viscous fluid in the cylindrical chamber will push each check valve against the second side surface of the corresponding blade, thereby closing the flow path by using each check valve. This allows the viscous fluid to move only through the gaps between the respective partition portions of the cylindrical chamber and the outer peripheral surface of the rotor body, and the gaps between the closed end (bottom surface) of the housing and the lower surfaces of the respective blades (the surfaces facing the closed end of the housing), thereby increasing the pressure on the viscous fluid in the portion facing the second side surface of each blade. As a result, a large damping torque is generated. Conversely, if a force is applied to the rotor to rotate the rotor in the direction from the second side surface of each blade to the first side surface (in the reverse direction), the viscous fluid flows into the corresponding flow path from the portion facing the first side surface of each blade and pushes up the corresponding check valve, thereby forming an open state of each flow path. Thus, the movement of the viscous fluid through the flow paths formed in the respective blades is also allowed, and therefore, the pressure on the viscous fluid in the portion facing the first end surface of each blade is not increased. As a result, a small damping torque is generated.

[0006] The rotary damper disclosed in Patent Document 1 further includes a damping force adjusting mechanism for adjusting the large damping torque generated when the rotor is subjected to a force that rotates the rotor in the forward direction. The damping force adjusting mechanism has an elastic member interposed between the open end of the housing and the lid, and a plurality of bolts for fixing the lid to the open end of the housing via the elastic member. A plurality of threaded holes are formed in the open end of the housing, and through holes are formed through the elastic member and the lid at positions corresponding to these threaded holes. The bolts are respectively inserted into the corresponding through holes penetrating the lid and the elastic member, and are screwed into the same threaded holes formed in the open end of the housing. The displacement of the rotor pushed into the cylindrical chamber of the housing by the lid is controlled according to the tightening degree of the bolts tightened respectively. Thus, the gap between the closed end of the housing and the lower surfaces of the respective blades is adjusted, and the large damping torque generated when the rotor is subjected to a force that rotates the rotor in the forward direction can be adjusted.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Patent Laid-Open No. 7-301272 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] However, since the damping force adjusting mechanism of the rotary damper described in Patent Document 1 has an elastic member between the open end of the housing and the lid, and a plurality of bolts for fixing the lid to the open end of the housing via the elastic member, the number of components of the rotary damper increases. In order to properly place the rotor in the cylindrical chamber, it is intended to tighten all the bolts evenly so that the lid can uniformly press the rotor over the entire surface of the lid. This makes the adjustment of the damping torque complicated.

[0012] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rotary damper that can easily adjust the damping torque caused by rotation with a simple structure.

[0013] Means for Solving the Problem

[0014] To solve the above problems, the present invention is a rotary damper configured to restrict the movement of the filled viscous fluid so as to generate a damping torque with respect to an applied rotational force. A screw-type lid screwed into the housing is adopted, and thus, by changing the amount of the screw of the lid screwed into the housing, the gap between the lid and each blade is adjusted to adjust the amount of the viscous fluid moving through these gaps. Thereby, the damping torque caused by rotation can be adjusted. In addition, an axial force generating member is disposed between each spaced portion of the lid and the cylindrical chamber. The axial force generating member includes an element that can be plastically deformed or elastically deformed and applies a reaction force to the lid. Thus, an axial force is generated by screwing the lid into the housing, thereby preventing the viscous fluid from leaking out through the threaded joint between the lid and the housing; and increasing the adjustment margin of the gap between the lid and each blade, thereby broadening the adjustment range of the damping torque.

[0015] For example, the present invention provides a rotary damper for restricting the movement of a viscous fluid so as to generate a damping torque with respect to an applied rotational force, the rotary damper having:

[0016] A housing having an open end on one side and including a cylindrical chamber defined therein, the cylindrical chamber being filled with the viscous fluid;

[0017] A rotor placed in the cylindrical chamber and capable of rotating relative to the cylindrical chamber; and

[0018] A lid mounted on the open end of the housing and holding the rotor and the viscous fluid together and sealing them in the cylindrical chamber.

[0019] The rotor has:

[0020] A cylindrical rotor body; and

[0021] The blade projects radially outward from the outer peripheral surface of the rotor body, and the front end surface of the blade is close to the side wall surface in the cylindrical chamber so as to partition the interior of the cylindrical chamber.

[0022] The housing has:

[0023] A partition portion that projects radially inward from the side wall surface in the cylindrical chamber, and the front end surface of the partition portion is close to the outer peripheral surface of the rotor body so as to partition the interior of the cylindrical chamber; and

[0024] A first threaded portion formed at the open end of the housing.

[0025] The cover has a second threaded portion formed on the cover and engaged with the first threaded portion formed at the open end of the housing.

[0026] The rotary damper further has an axial force generating member, which includes an element capable of plastic or elastic deformation and is located between the back surface of the cover and the surface of the partition portion facing the back surface of the cover, so as to generate an axial force by screwing the second threaded portion of the cover onto the first threaded portion of the housing. A gap is defined between the back surface of the cover and the surface of the blade facing the back surface of the cover as a flow path for restricting the movement of the viscous fluid, and the gap can be adjusted by adjusting the screwing amount of the second threaded portion of the cover on the first threaded portion of the housing.

[0027] Here, the rotary damper may also selectively have a first sealing member that seals the gap between the front end surface of the partition portion and the outer peripheral surface of the rotor. The rotary damper may also selectively have a second sealing member that seals the gap between the front end surface of the blade and the side wall surface in the cylindrical chamber.

[0028] The rotary damper may also have:

[0029] A flow path formed in the partition portion or the blade and penetrating both side surfaces of the partition portion or the blade along the rotation direction of the rotor; and

[0030] A check valve configured to close the flow path when the rotor rotates relative to the cylindrical chamber in the forward direction and open the flow path when the rotor rotates relative to the cylindrical chamber in the reverse direction.

[0031] Here, for the rotary damper having the first sealing member or the second sealing member, the check valve may be integrally formed with the first sealing member or the second sealing member.

[0032] Effects of the Invention

[0033] According to the present invention, by using a screw-fitting type lid that can be screw-fitted to a housing, the gap between the lid and the blades can be adjusted by adjusting the screw-fitting amount of the lid relative to the housing. Therefore, without increasing the number of components, the amount of movement of the viscous fluid can be adjusted with a simple structure and easy operation by means of this gap, thereby adjusting the damping torque caused by the applied rotation.

[0034] Furthermore, according to the present invention, an axial force generating member is disposed between the lid and the partition portion of the cylindrical chamber. The axial force generating member includes an element that can be plastically or elastically deformed and applies a reaction force to the lid. This makes it possible to screw-fit the lid to the housing so as to generate an axial force, thereby preventing the viscous fluid from leaking out through the threaded joint between the lid and the housing; and increasing the adjustment margin of the gap between the lid and each blade, thereby broadening the adjustment range of the damping torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 (A) to Figure 1 (C) are respectively a front view, a side view, and a rear view of a rotary damper 1 according to an embodiment of the present invention.

[0036] Figure 2 (A) is Figure 1 a cross-sectional view taken along line A-A of the rotary damper 1 shown in (A), Figure 2 (B) is Figure 1 a cross-sectional view taken along line B-B of the rotary damper 1 shown in (B).

[0037] Figure 3 (A) and Figure 3 (B) are respectively Figure 2 an enlarged view of part A and an enlarged view of part B of the rotary damper 1 shown in (A).

[0038] Figure 4 (A) is Figure 2 an enlarged view of part C of the rotary damper 1 shown in (A), Figure 4 (B) is Figure 2 an enlarged view of part D of the rotary damper 1 shown in (B).

[0039] Figure 5 (A) is a front view of the housing 11, Figure 5 (B) is Figure 5 a cross-sectional view taken along line C-C of the housing 11 shown in (A),Figure 5 (C) is the rear view of the housing 11, Figure 5 (D) is Figure 5 an enlarged view of part E of the housing 11 shown in (A), Figure 5 (E) is Figure 5 an enlarged sectional view taken along line D-D of the housing 11 shown in (A).

[0040] Figure 6 (A) and Figure 6 (B) are respectively the front view and the side view of the rotor 12; Figure 6 (C) is Figure 6 a sectional view taken along line E-E of the rotor 12 shown in (A).

[0041] Figure 7 (A) and Figure 7 (B) are respectively the front view and the side view of the first sealing member 13; Figure 7 (C) is Figure 7 a sectional view taken along line F-F of the first sealing member 13 shown in (A).

[0042] Figure 8 (A) and Figure 8 (B) are respectively the front view and the side view of the second sealing member 14; Figure 8 (C) is Figure 8 a sectional view taken along line G-G of the second sealing member 14 shown in (A).

[0043] Figure 9 (A) to Figure 9 (C) are respectively the front view, the side view and the rear view of the cover 15; Figure 9 (D) is Figure 9 a sectional view taken along line H-H of the cover 15 shown in (A).

[0044] Figure 10 (A) to Figure 10 (D) are respectively the front view, the top view, the bottom view and the side view of the axial force generating member 17; Figure 10 (E) is Figure 10 an enlarged sectional view taken along line I-I of the axial force generating member 17 shown in (C); Figure 10 (F) is Figure 10 an enlarged sectional view taken along line J-J of the axial force generating member 17 shown in (D).

[0045] Figure 11 (A) is an enlarged view of the axial force generating member 17 when viewed from the center of the rotational damper 1 according to an embodiment of the present invention, wherein the axial force generating member 17 is mounted on the protruding portion 18 of the partition portion 115 of the housing 11; Figure 11 (B) is Figure 11An enlarged cross-sectional view taken along line K-K of the axial force generating member 17 shown in (A). DETAILED DESCRIPTION

[0046] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0047] Figure 1 (A) to Figure 1 (C) are respectively a front view, a side view, and a rear view of the rotary damper 1 according to an embodiment of the present invention. Figure 2 (A) is Figure 1 A cross-sectional view taken along line A-A of the rotary damper 1 shown in (A), Figure 2 (B) is Figure 1 A cross-sectional view taken along line B-B of the rotary damper 1 shown in (B). Figure 3 (A) and Figure 3 (B) are respectively Figure 2 An enlarged view of part A and an enlarged view of part B of the rotary damper 1 shown in (A). Figure 4 (A) is Figure 2 An enlarged view of part C of the rotary damper 1 shown in (A), Figure 4 (B) is Figure 2 An enlarged view of part D of the rotary damper 1 shown in (B).

[0048] As shown in the figure, the rotary damper 1 according to the present invention includes: a housing 11; a rotor 12 rotatably accommodated in the housing 11 relative to the housing 11; a viscous fluid (not shown), such as silicone oil, filled in the housing 11; a lid 15 that holds the rotor 12 and the viscous fluid together and seals them in the housing 11; and a pair of axial force generating members 17.

[0049] Figure 5 (A) is a front view of the housing 11, Figure 5 (B) is Figure 5 A cross-sectional view taken along line C-C of the housing 11 shown in (A), Figure 5 (C) is a rear view of the housing 11, Figure 5 (D) is Figure 5 An enlarged view of part E of the housing 11 shown in (A), Figure 5 (E) is Figure 5 An enlarged cross-sectional view taken along line D-D of the housing 11 shown in (A).

[0050] As shown in the figure, the housing 11 is made of a metal, such as aluminum, and includes: a cylindrical chamber 111 defined inside the housing 11 and open at one end (for example, a cylindrical space with a bottom), and an opening 113 formed through the bottom 112 of the housing 11 for inserting the rotor 12. By inserting the lower end portion 123a of the rotor body 121 (as described later) (refer toFigure 6 ) is inserted into the opening 113 so that the rotary shaft 120 of the rotor 12 is aligned with the center line 110 of the cylindrical chamber 111, and the rotor 12 is placed in the cylindrical chamber 111 (see Figure 2 (A)). The side wall surface 114 in the cylindrical chamber 111 has a pair of partition portions 115 which are respectively formed along the center line 110 of the cylindrical chamber 111, and the partition portions 115 are arranged symmetrically about the center line 110 and project radially inward so that their respective front end surfaces 116 approach the outer peripheral surface 124 of the rotor body 121 (as described later) of the rotor 12 (see Figure 6 ), thereby partitioning the interior of the cylindrical chamber 111.

[0051] The first sealing member 13 as described below (see Figure 4 (B)) is mounted on each of the pair of partition portions 115. The pair of partition portions 115 has a raised portion 18 formed on each top surface 119 so that the axial force generating member 17 can be mounted, and the top surface 119 is the surface facing the back surface 153 of the cover 15 (see Figure 9 ). The top surface 180 of each raised portion 18 has a groove 181 formed thereon along the radial direction of the cylindrical chamber 111 so that the adjusting portion 174 (as described later) of the axial force generating member 17 can be inserted into the groove 181, and the groove bottom 182 of the groove 181 is located closer to the cover 15 than the top surface 119 of the corresponding partition portion 115. The two side surfaces 183 of each raised portion 18 arranged along the radial direction of the housing 11 include respective grooves 184 formed along the center line 110 of the cylindrical chamber 111 so that the pressing portion 175 (as described later) of the corresponding axial force generating member 17 can be mounted in the groove 184.

[0052] An internal thread portion 117 is formed as the first thread portion on the opening side 118 of the side wall surface 114 in the cylindrical chamber 111 and engages with the external thread portion 152 (as described later) of the cover 15 (see Figure 9 ).

[0053] Figure 6 (A) and Figure 6 (B) are respectively the front view and the side view of the rotor 12; Figure 6 (C) is Figure 6 the E-E sectional view of the rotor 12 shown in

[0054] As shown in the figure, the rotor 12 made of a thermoplastic resin, such as a polyamide resin, has a cylindrical rotor body 121 and a pair of vanes (rotating vanes) 122. The pair of vanes 122 are formed symmetrically with respect to the rotation axis 120 of the rotor 12. The vanes 122 are arranged along the rotation axis 120 of the rotor 12 and are formed to protrude radially outward from the outer peripheral surface 124 of the rotor body 121 so that their respective front end faces 125 approach the side wall surface 114 of the cylindrical chamber 111 in the housing 11, thereby partitioning the interior of the cylindrical chamber 111. Each vane 122 has a flow path 126 that penetrates both side surfaces 127a, 127b of the vane 122 along the rotation direction of the rotor 12. The second sealing member 14 described later is installed on each of the pair of vanes 122 (see Figure 4 (B)).

[0055] The rotor body 121 includes a through hole 128 centered on the rotation axis 120 so that a hexagonal shaft (not shown) for transmitting an external rotational force to the rotor 12 can be inserted. The lower end portion 123a of the rotor body 121 is rotatably inserted into the opening 113 formed in the bottom 112 of the cylindrical chamber 111 of the housing 11 (see Figure 4 (A)), and the upper end portion 123b of the rotor body 121 is rotatably inserted into the opening 150 (described later) of the lid 15 (see Figure 9 ) (see Figure 3 (A), (B)).

[0056] To prevent the viscous fluid from leaking out through the opening 113 of the cylindrical chamber 111, a sealing member, such as an O-ring 16a, can be provided between the lower end portion 123a of the rotor body 121 and the opening 113 of the cylindrical chamber 111 (refer to Figure 4 (A)).

[0057] Figure 7 (A) and Figure 7 (B) are the front view and side view of the first sealing member 13 respectively, Figure 7 (C) is Figure 7 the F-F cross-sectional view of the first sealing member 13 shown in

[0058] As shown in the figure, each first sealing member 13 has a U-shaped configuration so that it can be installed on a partition portion 115 formed in the cylindrical chamber 111 of the housing 11, and its bottom 130 is located between the front end face 116 of the corresponding partition portion 115 and the outer peripheral surface 124 of the rotor body 121 of the rotor 12, thereby filling the gap between them (see Figure 4(B). Each first sealing member 13 is located between the housing 11 and the rotor 12 that can rotate relative to each other. Therefore, a resin with excellent slidability, such as polyamide, can be used as a preferred material.

[0059] Figure 8 (A) and Figure 8 (B) are respectively the front view and the side view of the second sealing member 14; Figure 8 (C) is Figure 8 the G-G sectional view of the second sealing member 14 shown in

[0060] As shown in the figure, each second sealing member 14 has a U-shaped configuration so as to be mounted on the blade 122 of the rotor 12, and includes: a bottom 140 having a width t2 greater than the width t1 of the blade 122 in the rotational direction (see Figure 6 (A)); a first leg 143 integrally formed at one edge 141 of the bottom 140 and having a width t4 greater than the radial width t3 of the flow path 126 formed in the blade 122 (see Figure 6 (B)); and a second leg 144 integrally formed at the other edge 142 of the bottom 140 and having a width t5 smaller than the radial width t3 of the flow path 126 formed in the blade 122.

[0061] Each second sealing member 14 mounted on the blade 122 places its bottom 140 between the front end face 125 of the corresponding blade 122 and the side wall face 114 of the cylindrical chamber 111 in the housing 11, thereby closing the gap therebetween (see Figure 4 (B)). As shown in Figure 2 (B), when the rotor 12 rotates in the forward direction N with respect to the cylindrical chamber 111 in the housing 11, for each second sealing member, the first leg 143 abuts against one side face 127a of the corresponding blade 122, thereby closing the corresponding flow path 126 formed in the corresponding blade 122. Therefore, when the rotor 12 rotates in the reverse direction R with respect to the cylindrical chamber 111 in the housing 11, for each second sealing member 14, the first leg 143 moves away from one side face 127a of the corresponding blade 122, and then, the second leg 144 abuts against the other side face 127b of the corresponding blade 122, thereby opening the flow path 126 formed in the corresponding blade 122. The second sealing member 14 is located between the housing 11 and the rotor 12 that can rotate relative to each other. Therefore, a resin with excellent slidability, such as polyamide, can be used as a preferred material.

[0062] Figure 9 (A) to Figure 9 (C) are respectively the front view, the side view, and the rear view of the cover 15;Figure 9 (D) is Figure 9 a sectional view taken along line H-H of the cover 15 shown in (A).

[0063] As shown in the figure, the cover 15 has an opening 150 at a position facing the opening 113 for inserting the upper end portion 123b of the rotor body 121 of the rotor 12 into the opening 150. The opening 113 is formed at the bottom 112 of the cylindrical chamber 111 of the housing 11. The cover 15 has an external thread portion 152 formed on its outer peripheral surface 151 as a second thread portion, so that the external thread portion 152 can be engaged with the internal thread portion 117 on the inner side of the opening side 118 of the side wall surface 114 of the cylindrical chamber 111. A clearance G1 (see Figure 3 (B)) is formed between the lower surface (rear surface) 153 of the cover 15 and the top surface 129 of each blade 122 of the rotor 12 and serves as a flow path for the viscous fluid filled in the cylindrical chamber 111. By adjusting the amount of screw engagement of the cover 15 screwed into the housing 11 (the amount of engagement between the external thread portion 152 of the cover 15 and the internal thread portion 117 of the housing 11), these clearances G1 serving as flow paths for the viscous fluid can be adjusted.

[0064] To prevent the viscous fluid from leaking out through the opening 150 of the cover 15, a sealing member, such as an O-ring 16b, can be provided between the upper end portion 123b of the rotor body 121 of the rotor 12 and the opening 150 of the cover 15. Similarly, to prevent the viscous fluid from leaking out through the threaded joint between the external thread portion 152 of the cover 15 and the internal thread portion 117 of the cylindrical chamber 111 in the housing 11, a sealing member, such as an O-ring 16c, can be provided between the outer peripheral surface 151 of the cover 15 and the side wall surface 114 in the cylindrical chamber 111 (see Figure 3 (A) and Figure 3 (B)).

[0065] Figure 10 (A) to Figure 10 (D) are respectively the front view, top view, bottom view and side view of the axial force generating member 17; Figure 10 (E) is Figure 10 an enlarged sectional view taken along line I-I of the axial force generating member 17 shown in (C); Figure 10 (F) is Figure 10 an enlarged sectional view taken along line J-J of the axial force generating member 17 shown in (D). Figure 11 (A) is an enlarged view of the axial force generating member 17 when viewed from the center of the rotary damper 1 according to an embodiment of the present invention (corresponding to Figure 5 a view along the direction of arrow F in (A)), wherein the axial force generating member 17 is mounted on the protruding portion 18 of the partition portion 115 of the housing 11; Figure 11 (B) isFigure 11 An enlarged cross-sectional view taken along line K-K of the axial force generating member 17 shown in (A).

[0066] Each of the axial force generating members 17 is made of a material capable of plastic deformation or a material capable of elastic deformation. The materials capable of plastic deformation include thermoplastic resins such as polyoxymethylene and sintered metals, and the materials capable of elastic deformation include natural rubber, synthetic rubber, and synthetic resin elastomers. Each of the axial force generating members 17 is mounted on a projection 18 on the top surface 119 of a corresponding one of a pair of partition portions 115 formed in the housing 11, and is interposed between the top surface 119 of the corresponding partition portion 115 and the back surface 153 of the lid 15, thereby filling the gap between the back surface 153 of the lid 15 and the top surface 119 of the corresponding partition portion 115. By screwing the lid 15 onto the housing 11, the axial force generating member 17 can be caused to generate an axial force.

[0067] As shown in the figure, each of the axial force generating members 17 includes a rectangular main body 170, a pair of arm portions 173, and an adjusting portion 174. The main body 170 has a top surface 171 that contacts the back surface 153 of the lid 15. The pair of arm portions 173 are formed on the lower surface 172 of the main body 170 so as to sandwich both side surfaces 183 of a projection 18 formed on the top surface 119 of the corresponding partition portion 115 of the housing 11 and clamp the projection 18. The adjusting portion 174 is located between the pair of arm portions 173 and projects toward the projection 18 so as to be inserted into a groove 181 of the projection 18.

[0068] The pair of arm portions 173 each have a pressing portion 175 so as to be pushed into and contact a groove 184 formed in both side surfaces 183 of the projection 18. When the axial force generating member 17 is mounted on the projection 18, the corresponding pressing portions 175 and the grooves 184 in both side surfaces 183 of the projection 18 are used together to ensure positioning. These pressing portions 175 cause the pair of arm portions 173 to firmly clamp the axial force generating member 17 so that the axial force generating member 17 does not fall off the projection 18. The pair of arm portions 173 each have a length L4 (<L2 + L3) that is less than the sum of a length L2 and a length L3 (see Figure 5 (E)). The length L2 is the length of the adjusting portion 174, and the length L3 is the length from the top surface 119 of the partition portion 115 to the bottom 182 of the groove 181 of the projection 18 formed on the top surface 119.

[0069] The adjusting portion 174 has a depth greater than the depth L1 of the groove 181 of the projection 18 formed on the top surface 119 of the partition portion 115 (see Figure 5(E) a length L2 (>L1), and the width of the end 176 of the adjusting portion 174 in the thickness direction is narrower than the width of the base portion 177 in the thickness direction. Here, the groove 181 of the convex portion 18 has a size capable of generating plastic or elastic deformation at the end 176 of the adjusting portion 174. The two side portions 179 of the base portion 177 of the adjusting portion 174 in the thickness direction have pressing surfaces 178 so that the pressing surfaces 178 can contact and press the two inner side walls 185 of the groove 181 of the convex portion 18. These pressing surfaces 178 fit the adjusting portion 174 into the groove 181 of the convex portion 18, thereby ensuring more reliably preventing the axial force generating member 17 from falling off the convex portion 18.

[0070] Since each of the pair of arm portions 173 has a length L4 that is less than the sum of the length L2 of the adjusting portion 174 and the length L3 from the top surface 119 of the partition portion 115 to the bottom 182 of the groove 181 of the convex portion 18, and the adjusting portion 174 has a length L2 that is longer than the depth L1 of the groove 181 of the convex portion 18, the end 176 of the adjusting portion 174 contacts the bottom 182 of the groove 181 of the convex portion 18 without the pair of arm portions 173 contacting the top surface 119 of the partition portion 115. Since the groove 181 of the convex portion 18 has a size capable of generating plastic or elastic deformation at the end 176 of the adjusting portion 174, by screwing the cover 15 onto the housing 11, while generating an axial force, plastic or elastic deformation is actively generated not only in the main body 170 but also at the end 176 of the adjusting portion 174. Therefore, the margin of the clearance G1 between the back surface 153 of the adjusting cover 15 and the top surface 129 of each blade 122 is increased.

[0071] In the rotary damper 1 having the above structure, when the rotor 12 rotates in the forward direction N with respect to the cylindrical chamber 111 in the housing 11 (see Figure 2 (B)), the first leg portions 143 of the respective second sealing members 14 abut against one side surface 127a of the corresponding blade 122, thereby closing the flow path 126 formed in the corresponding blade 122. At this time, each first sealing member 13 mounted on the partition portion 115 of the cylindrical chamber 111 of the housing 11 closes the clearance between the front end surface 116 of the corresponding partition portion 115 and the outer peripheral surface 124 of the rotor body 121 of the rotor 12, and each second sealing member 14 mounted on the blade 122 of the rotor 12 closes the clearance between the front end surface 125 of the corresponding blade 122 and the side wall surface 114 of the cylindrical chamber 111 in the housing 11 (see Figure 4(B)). Therefore, only the movement of the viscous fluid filled in the cylindrical chamber 111 through the gap G1 between the back surface 153 of the cover 15 and the top surface 129 of each blade 122 is allowed. Thus, the pressure of the viscous fluid in the regions 111a (see Figure 2 (B)) separated by the corresponding blades 122 and the partition portions 115 located in the forward direction N with respect to the corresponding blades 122 increases. As a result, a large damping torque is generated.

[0072] By adjusting the amount of screw fitting of the cover 15 into the housing 11 (the amount of engagement between the external thread portion 152 of the cover 15 and the internal thread portion 117 of the housing 11), the gap G1 between the back surface 153 of the cover 15 and the top surface 129 of each blade 122 can be adjusted. Thus, by adjusting the movement amount of the viscous fluid by means of the gap G1, the damping torque caused by the applied rotation can be adjusted.

[0073] Furthermore, the axial force generating members 17 are respectively located between the back surface 153 of the cover 15 and the top surface 119 of the corresponding partition portions 115 to apply a reaction force to the cover 15; therefore, by screw-fitting the cover 15 into the housing 11, the axial force generating members 17 can generate an axial force, thereby preventing the viscous fluid from leaking out through the threaded joint portion between the external thread portion 152 of the cover 15 and the internal thread portion 117 of the housing 11, and increasing the margin for adjusting the gap G1 and broadening the adjustment range of the damping torque.

[0074] Conversely, when the rotor 12 rotates in the reverse direction R with respect to the cylindrical chamber 111 in the housing 11 (see Figure 2 (B)), the first legs 143 of the respective second sealing members 14 move away from one side surface 127a of the corresponding blade 122, thereby opening the flow path 126 formed in the corresponding blade 122. Thus, the viscous fluid filled in the cylindrical chamber 111 can move not only through the gap G1 between the back surface 153 of the cover 15 and the top surface 129 of each blade 122, but also through the flow path 126 formed in each blade 122. Therefore, it does not cause the pressure of the viscous fluid in the respective regions 111 separated by the corresponding blades 122 and the partition portions 115 located in the reverse direction R with respect to the corresponding blades 122 to increase (see Figure 2 (B)). As a result, a small damping torque is generated.

[0075] The above describes the embodiments of the present invention.

[0076] According to the present embodiment, in the rotary damper 1 for restricting the movement of the filled viscous fluid to generate a damping torque against the applied rotational force, a screw-fitting type lid 15 that can be screw-fitted into the housing 11 is employed. Thus, the clearance G1 between the back surface 153 of the lid 15 and the top surface 129 of each vane 122 can be adjusted by the amount of screw-fitting of the lid 15 into the housing 11. Therefore, without increasing the number of components of the rotary damper, the amount of viscous fluid flowing through each clearance G1 can be adjusted with a simple structure and easy operation, so as to adjust the damping torque caused by the applied rotation.

[0077] According to the present embodiment, the axial force generating member 17 includes an element that can plastically or elastically deform between the back surface 153 of the lid 15 and the top surface 119 of the partition portion 115 to apply a reaction force to the lid 15. Thus, by screw-fitting the lid 15 into the housing 11, the axial force generating member 17 can generate an axial force, thereby preventing the viscous fluid from leaking out through the threaded engagement portion between the external threaded portion 152 of the lid 15 and the internal threaded portion 117 of the housing 11, and increasing the margin for adjusting the clearance G1, thereby broadening the adjustment range of the damping torque. In addition, the axial force generated by the axial force generating member 17 tightly fits the lid 15 and the housing 11 together, so that the lid 15 can be prevented from rotating easily even when an external force is applied in any rotational direction of the lid 15.

[0078] In the present embodiment, a convex portion 18 is provided on the top surface 119 of the partition portion 115, and the axial force generating member 17 is provided with a pair of arm portions 173 for clamping and holding the convex portion 18. This can facilitate the installation of the axial force generating member 17 to the corresponding partition portion 115.

[0079] In the present invention, the axial force generating member 17 is provided with an adjusting portion 174 between the pair of arm portions 173. The adjusting portion 174 is formed to protrude toward the convex portion 18 on the top surface 119 of the corresponding partition portion 115 so as to be inserted into the groove 181 of the convex portion 18 and abut against the bottom surface 182 of the groove 18, and the groove 181 of the convex portion 18 has a size that can plastically or elastically deform the end 176 of the adjusting portion 174. Thus, by screw-fitting the lid 15 into the housing 11, the end 176 of the adjusting portion 174 is pressed against the bottom surface 182 of the groove 181 and actively plastically or elastically deforms, thereby further increasing the adjustment margin for the clearance G1.

[0080] In the present embodiment, a pair of arm portions 173 of the axial force generating member 17 each have a pressing portion 175 so as to be pushed into and press a groove 184 formed in both side surfaces 183 of the protruding portion 18, and the protruding portion 18 is formed on the top surface 119 of the partitioning portion 115. These pressing portions 175 can firmly hold the axial force generating member 17 by the pair of arm portions 173, so that the axial force generating member 17 does not fall off from the protruding portion 18. In addition, when the axial force generating member 17 is mounted on the protruding portion 18, these pressing portions 175 are used together with the grooves 184 formed in both side surfaces 183 of the protruding portion 18 to ensure positioning, so that the axial force generating member 17 is properly mounted on the protruding portion 18.

[0081] In the present embodiment, the adjusting portion 174 of the axial force generating member 17 has pressing surfaces 178 on both side portions 179 of its base portion 177, and the pressing surfaces 178 contact and press against both inner side walls 185 of the groove 181 of the protruding portion 18. These pressing surfaces 178 fit the adjusting portion 174 into the groove 181 of the protruding portion 18, thereby ensuring reliable prevention of the axial force generating member 17 from falling off the protrusion 18.

[0082] Furthermore, according to the present embodiment, the first sealing member 13 and the second sealing member 14 are made of a resin having excellent sliding properties, such as polyamide. Thus, the first sealing member 13 and the second sealing member 14 serve as sliding bearings that respectively provide sliding support for the outer peripheral surface 124 of the rotor body 121 of the rotor 12. Thereby, play generated, for example, due to the eccentricity of the hexagonal shaft for transmitting an external rotational force to the rotor 12 is absorbed, and the hexagonal shaft can rotate smoothly.

[0083] The present invention includes, but is not limited to, the above embodiments. It is obvious to those skilled in the art that various changes can be made without departing from the scope of the present invention.

[0084] For example, in the above embodiment, an example is described in which the gap G1 between the back surface 153 of the lid 15 and the top surface 129 of each blade 122 is also used as a flow path for a viscous fluid other than the flow path 126 formed in each blade 122; however, the present invention is not limited to this example. The axial force generating member 17 can be arranged so as not to close the gap between the back surface 153 of the lid 15 and the top surface 119 of each partitioning portion 115. Thus, not only the gap G1 between the back surface 153 of the lid 15 and the top surface 129 of the blade 122, but also the gap between the back surface 153 of the lid 15 and the top surface 119 of each partitioning portion 115 can be used as a flow path for a viscous fluid other than the flow path 126 formed in the blade 122.

[0085] In this embodiment, an example in which the cylindrical chamber 111 is provided with a pair of partition portions 115 and the rotor 12 is provided with a pair of blades 122 has been described; however, the present invention is not limited to this example. As long as the number of the partition portions 115 formed in the cylindrical chamber 111 is the same as the number of the blades 122 formed in the rotor 12, the number of the formed partition portions 115 and the number of the formed blades 122 may each be 1, 3, or more, respectively.

[0086] In this embodiment, each of the second seal members 14 attached to the blades 122 functions as a check valve for opening and closing the flow path 126 formed in the corresponding blade 122, but the present invention is not limited thereto. The check valve may be provided separately from the second seal member 14 so that when the rotor 12 rotates in the forward direction N with respect to the cylindrical chamber 111 in the housing 11, the flow path 126 formed in the blade 122 is closed, and when the rotor 12 rotates in the reverse direction R with respect to the cylindrical chamber 111 in the housing 11, the flow path 126 formed in the blade 122 is opened.

[0087] The present invention includes but is not limited to this embodiment. In this embodiment, the blade 122 includes flow paths 126 that respectively penetrate both side surfaces 127a and 127b of the corresponding blade 122 along the rotation direction of the rotor 12. Instead of or in addition to the blade 122, the partition portion 115 may include flow paths that respectively penetrate both side surfaces of the corresponding partition portion 115 along the rotation direction of the rotor 12. In this case, a check valve may be installed so that when the rotor 12 rotates in the forward direction N with respect to the cylindrical chamber 111 in the housing 11, the flow path formed in the corresponding partition portion 115 is closed, and when the rotor 12 rotates in the reverse direction R with respect to the cylindrical chamber 111 in the housing 11, the flow path formed in the corresponding partition portion 115 is opened.

[0088] When a flow path is formed in the partition portion 115, the first sealing member 13 may respectively have a shape similar to that of the second sealing member 14, that is, a shape including the following parts: a bottom portion having a width larger than the circumference of the inner edge of the corresponding partition portion 115; a first leg portion integrally formed at one edge of the bottom portion and having a width larger than the radial width of the flow path formed in the partition portion 115; and a second leg portion integrally formed at the other edge of the bottom portion and having a width smaller than the radial width of the flow path formed in the corresponding partition portion 115. The first sealing member 13 can be used as a check valve capable of performing the following operations: when the rotor 12 rotates in the forward direction N with respect to the cylindrical chamber 111 in the housing 11, the leg portion of the first sealing member 13 abuts against one side surface of the partition portion 115, thereby closing the flow path formed in the partition portion 115; conversely, when the rotor 12 rotates in the reverse direction R with respect to the cylindrical chamber 111 in the housing 11, the first leg portion of the first sealing member moves away from one side surface of the partition portion 115, and the second leg portion abuts against the other side surface of the partition portion 115, thereby opening the flow path formed in the partition portion 115.

[0089] When the flow path 126 is not formed in the blade 122, the second sealing member 14 can have any shape as long as it can close the gap between the front end surface 125 of the blade 122 and the side wall surface 114 of the cylindrical chamber 111 in the housing 11.

[0090] The present embodiment has been described by taking a so-called unidirectional rotary damper as an example. During the rotation of the rotor 12 in the forward direction N with respect to the cylindrical chamber 111 in the housing 11, the unidirectional rotary damper can generate a large damping torque, and during the rotation of the rotor 12 in the reverse direction R with respect to the cylindrical chamber 111 in the housing 11, the unidirectional rotary damper can generate a small damping torque. However, the present invention is not limited to this example. The present invention can also be used for a so-called bidirectional rotary damper that can generate a large damping torque both in the forward direction N and the reverse direction R. In this case, the flow path 126 is omitted from the blade 122 of the rotor 12. Each second sealing member 14 can only close the gap between the front end surface 125 of the corresponding blade 122 and the side wall surface 114 of the cylindrical chamber 111 in the housing 11.

[0091] The present invention includes but is not limited to the present embodiment in which the first sealing member 13 is installed on the partition portion 115 located in the cylindrical chamber 111 in the housing 11. The first sealing member 13 can be omitted. Similarly, although the second sealing member 14 is installed on the blade 122 of the rotor 12 in the present embodiment, the second sealing member 14 can be omitted.

[0092] In the present embodiment, each axial force generating member 17 includes an element capable of plastic or elastic deformation between the back surface 153 of the lid 15 and the top surface 119 of the corresponding partition portion 115. Therefore, an axial force is generated by screwing the lid 115 onto the housing 11. However, the present invention is not limited to this embodiment. The housing 11 may be made of a thermoplastic resin, and as a part integral with the housing 11, it includes a protruding portion on the top surface 119 of each partition portion 115, which abuts against the back surface 153 of the lid 15 and functions as an axial force generating portion. In this case, by screwing the lid 15 onto the housing 11, the axial force generating portion (the protruding portion) generates an axial force, thereby preventing the viscous fluid from leaking out through the threaded engagement portion between the external threaded portion 152 of the lid 15 and the internal threaded portion 117 of the housing 11. Moreover, the axial force generating portion plastically or elastically deforms, thereby increasing the margin for adjusting the gap G1 and broadening the adjustment range of the damping torque.

[0093] In the present embodiment, the internal threaded portion 117 is formed as a first threaded portion on the opening side 118 of the inner peripheral surface (the side wall surface 114 within the cylindrical chamber 111) of the housing 11, and the external threaded portion 152 is formed as a second threaded portion on the outer peripheral surface 151 of the lid 15 so as to engage with the internal threaded portion 117 of the housing 11. However, the present invention is not limited thereto. For example, the lid 15 may have a bottle cap shape (a hollow cylindrical shape with a bottom); in this case, the internal threaded portion may be formed as a second threaded portion on the inner peripheral surface of the hollow cylindrical portion of the lid 15, and the external threaded portion may be formed as a first threaded portion on the opening side 118 of the outer peripheral surface of the housing 11 so as to engage with the internal threaded portion of the lid 15.

[0094] The rotational damper 1 according to the present embodiment can be widely applied to, for example, seats having a tilting function used in automobiles, railway vehicles, airplanes, ships, etc. Furthermore, the rotational damper 1 can also be widely applied to any device other than seats having a tilting function, as long as the device needs to provide damping only during the rotation of a rotatable body in one direction of bidirectional rotation.

[0095] Explanation of reference numerals

[0096] 1: Rotary damper; 11: Housing; 12: Rotor; 13: First sealing member; 14: Second sealing member; 15: Cover; 16a, 16b, 16c: O-ring; 17: Axial force generating member; 18: Protrusion; 111: Cylindrical chamber; 112: Bottom of the cylindrical chamber 111; 113: Opening of the cylindrical chamber 111; 114: Side wall surface inside the cylindrical chamber 111; 115: Partition; 116: Front end surface of the partition 115; 117: Internal thread portion; 118: Opening side of the cylindrical chamber 111; 119: Top surface of the partition 115; 121: Rotor body; 122: Vane; 123a, 123b: Ends of the rotor body 121; 124: Outer peripheral surface of the rotor body; 125: Front end surface of the vane 122; 126: Flow path; 127a, 127b: Side surfaces of the vane 122; 128: Through hole in the rotor body 121; 129: Top surface of the vane 122; 130: Bottom of the first sealing member 13; 140: Bottom of the second sealing member 14; 141, 142: Edges of the bottom 140 of the second sealing member 14; 143: First leg of the second sealing member 14; 144: Second leg of the second sealing member 14; 150: Opening of the cover 15; 151: Outer peripheral surface of the cover 15; 152: External thread portion; 153: Lower surface of the cover 15; 170: Main body of the axial force generating member 17; 171: Top surface of the main body 171; 172: Lower surface of the main body 17; 173: Arm portion; 174: Adjusting portion; 175: Pushing portion; 176: End of the adjusting portion 174; 177: Base of the adjusting portion 174; 178: Pushing portion; 179: Side portion of the base 177; 180: Top surface of the protrusion 18; 181: Groove; 182: Bottom of the groove; 183: Side surface of the protrusion 18; 184: Groove; 185: Inner side wall of the groove 181.

Claims

1. A rotary damper for restricting the movement of a viscous fluid to generate a damping torque relative to an applied rotational force, the rotary damper comprising: A housing having an open end on one side and including a cylindrical chamber formed therein, the cylindrical chamber being filled with the viscous fluid; A rotor disposed within the cylindrical chamber and capable of rotating relative to the cylindrical chamber; And A cover mounted to the open end of the housing and holding the rotor and the viscous fluid together in a sealed manner within the cylindrical chamber; The rotor includes: A cylindrical rotor body; and Blades that project radially outward from the outer peripheral surface of the rotor body, and the front end surfaces of the blades are close to the side wall surfaces within the cylindrical chamber so as to partition the interior of the cylindrical chamber; The housing includes: A partitioning portion that projects radially inward from the side wall surface within the cylindrical chamber, and the front end surface of the partitioning portion is close to the outer peripheral surface of the rotor body so as to partition the interior of the cylindrical chamber; and A first threaded portion formed at the open end of the housing; The cover includes a second threaded portion formed on the cover and meshing with the first threaded portion formed at the open end of the housing; The rotary damper further includes an axial force generating member including an element capable of plastic or elastic deformation and located between the back surface of the cover and the surface of the partitioning portion facing the back surface of the cover so as to generate an axial force by screwing the second threaded portion of the cover onto the first threaded portion of the housing; Wherein, a gap is defined between the back surface of the cover and the surface of the blade facing the back surface of the cover as a flow path for restricting the movement of the viscous fluid, and the gap can be adjusted by adjusting the amount of screw engagement between the second threaded portion of the cover and the first threaded portion of the housing.

2. The rotary damper according to claim 1, Among them, The partitioning portion includes a raised portion on the surface facing the back surface of the cover, and the raised portion is used for mounting the axial force generating member to the partitioning portion.

3. The rotary damper according to claim 2, Among them, The axial force generating member further includes an adjusting portion that projects toward the raised portion; and The raised portion includes an insertion portion having a bottom surface that contacts the end of the adjusting portion of the axial force generating member inserted into the insertion portion.

4. The rotary damper according to claim 3, Among them, The end of the adjusting portion is narrower than the base of the adjusting portion; The adjusting portion includes a pressing portion formed at the base of the adjusting portion and pressing the side wall surface of the insertion portion.

5. The rotary damper according to claim 2, wherein, The axial force generating member includes a pair of arm portions that clamp and hold the raised portion.

6. The rotary damper according to claim 3, wherein, The axial force generating member includes a pair of arm portions that clamp and hold the raised portion.

7. The rotary damper according to claim 4, wherein, The axial force generating member includes a pair of arms that clamp and hold the convex portion.

8. The rotary damper according to claim 5, Among them, Each of the pair of arms includes a pressing portion that presses against a side surface of the convex portion.

9. The rotary damper according to claim 6, Among them, Each of the pair of arms includes a pressing portion that presses against a side surface of the convex portion.

10. The rotary damper according to claim 7, Among them, Each of the pair of arms includes a pressing portion that presses against a side surface of the convex portion.

11. The rotary damper according to claim 1, Among them, The housing is made of a thermoplastic resin; and The axial force generating member is integrally formed with the partition portion.

12. The rotary damper according to any one of claims 1 to 11, further comprising a first sealing member that fills a gap between a front end surface of the partition portion and an outer peripheral surface of the rotor body.

13. The rotary damper according to any one of claims 1 to 11, further comprising a second sealing member that seals a gap between a front end surface of the blade and a side wall surface in the cylindrical chamber.

14. The rotary damper according to claim 12, further comprising a second sealing member that seals a gap between a front end surface of the blade and a side wall surface in the cylindrical chamber.

15. The rotary damper according to any one of claims 1 to 11, further comprising: A first flow path that is formed in the partition portion and penetrates both side surfaces of the partition portion along the rotation direction of the rotor; And A first check valve that is configured to close the first flow path when the rotor rotates in the forward direction relative to the cylindrical chamber, and to open the first flow path when the rotor rotates in the reverse direction relative to the cylindrical chamber.

16. The rotary damper according to claim 12, further comprising: A first flow path that is formed in the partition portion and penetrates both side surfaces of the partition portion along the rotation direction of the rotor; And A first check valve that is configured to close the first flow path when the rotor rotates in the forward direction relative to the cylindrical chamber, and to open the first flow path when the rotor rotates in the reverse direction relative to the cylindrical chamber.

17. The rotary damper according to claim 13, further comprising: A first flow path that is formed in the partition portion and penetrates both side surfaces of the partition portion along the rotation direction of the rotor; And A first check valve that is configured to close the first flow path when the rotor rotates in the forward direction relative to the cylindrical chamber, and to open the first flow path when the rotor rotates in the reverse direction relative to the cylindrical chamber.

18. The rotary damper according to claim 14, further comprising: A first flow path that is formed in the partition portion and penetrates both side surfaces of the partition portion along the rotation direction of the rotor; And A first check valve configured to close the first flow path when the rotor rotates in the forward direction relative to the cylindrical chamber and to open the first flow path when the rotor rotates in the reverse direction relative to the cylindrical chamber.

19. The rotary damper according to any one of claims 1 to 11, further comprising: A second flow path formed in the blade and penetrating both side surfaces of the blade along the rotation direction of the rotor; And A second check valve configured to close the second flow path when the rotor rotates in the forward direction relative to the cylindrical chamber and to open the second flow path when the rotor rotates in the reverse direction relative to the cylindrical chamber.

20. The rotary damper according to claim 12, further comprising: A second flow path formed in the blade and penetrating both side surfaces of the blade along the rotation direction of the rotor; And A second check valve configured to close the second flow path when the rotor rotates in the forward direction relative to the cylindrical chamber and to open the second flow path when the rotor rotates in the reverse direction relative to the cylindrical chamber.

21. The rotary damper according to claim 13, further comprising: A second flow path formed in the blade and penetrating both side surfaces of the blade along the rotation direction of the rotor; And A second check valve configured to close the second flow path when the rotor rotates in the forward direction relative to the cylindrical chamber and to open the second flow path when the rotor rotates in the reverse direction relative to the cylindrical chamber.

22. The rotary damper according to claim 14, further comprising: A second flow path formed in the blade and penetrating both side surfaces of the blade along the rotation direction of the rotor; And A second check valve configured to close the second flow path when the rotor rotates in the forward direction relative to the cylindrical chamber and to open the second flow path when the rotor rotates in the reverse direction relative to the cylindrical chamber.

23. The rotary damper according to claim 15, further comprising: A second flow path formed in the blade and penetrating both side surfaces of the blade along the rotation direction of the rotor; And A second check valve configured to close the second flow path when the rotor rotates in the forward direction relative to the cylindrical chamber and to open the second flow path when the rotor rotates in the reverse direction relative to the cylindrical chamber.

24. The rotary damper according to claim 16, further comprising: A second flow path formed in the blade and penetrating both side surfaces of the blade along the rotation direction of the rotor; And A second check valve configured to close the second flow path when the rotor rotates in the forward direction relative to the cylindrical chamber and to open the second flow path when the rotor rotates in the reverse direction relative to the cylindrical chamber.

25. The rotary damper according to claim 17, further comprising: A second flow path that is formed in the vane and penetrates both side surfaces of the vane along the rotation direction of the rotor; and A second check valve configured to close the second flow path when the rotor rotates relative to the cylindrical chamber in the forward direction, and to open the second flow path when the rotor rotates relative to the cylindrical chamber in the reverse direction.

26. The rotary damper according to claim 18, further comprising: A second flow path that is formed in the vane and penetrates both side surfaces of the vane along the rotation direction of the rotor; and A second check valve configured to close the second flow path when the rotor rotates relative to the cylindrical chamber in the forward direction, and to open the second flow path when the rotor rotates relative to the cylindrical chamber in the reverse direction.

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