本発明において、前記弁体は、径方向内側の第１端部が前記回転軸に支持された状態で、前記ロータの軸線周りの回転によって、径方向外側の第２端部が前記ケースの内周面から離間する開姿勢と、前記第２端部が前記ケースの内周面と接する閉姿勢と、に切り換わる態様を採用することができる。
In the present invention, the valve body is configured such that the second end portion on the outer side in the radial direction is the inner side of the case by rotation around the axis of the rotor in a state where the first end portion on the inner side in the radial direction is supported by the rotation shaft. It is possible to adopt a mode in which switching is made between an open posture that is separated from the peripheral surface and a closed posture in which the second end portion is in contact with the inner peripheral surface of the case.
弁体５０は、樹脂製であり、径方向内側で溝４６０において中心軸線Ｌと平行な軸線周りに回転可能に支持された断面略円形の第１端部５１と、第１端部５１から径方向外側に突出した第２端部５２とを有している。第２端部５２は、第１凸部４６１に被さるように第１方向Ａ（便座５の閉方向Ｓ）に向けて傾いている。第２端部５２の先端部は、第１凸部４６１および第２凸部４６２より径方向外側に位置する。このように構成した弁体５０は、径方向内側の第１端部５１が回転軸４０に支持された状態で、ロータ３０の軸線Ｌ周りの回転によって、径方向外側の第２端部５２がケース２０の内周面２２０から離間する開姿勢と、第２端部５２がケース２０の内周面２２０と接する閉姿勢とに切り換わる。
The valve body 50 is made of resin and has a first end portion 51 having a substantially circular cross section that is rotatably supported around an axis parallel to the central axis L in the groove 460 on the radially inner side, and a diameter from the first end portion 51. And a second end portion 52 protruding outward in the direction. The second end 52 is inclined toward the first direction A (the closing direction S of the toilet seat 5) so as to cover the first convex portion 461. The distal end portion of the second end portion 52 is located on the radially outer side from the first convex portion 461 and the second convex portion 462. In the valve body 50 configured as described above, the second end 52 on the radially outer side is rotated by the rotation around the axis L of the rotor 30 with the first end 51 on the radially inner side being supported by the rotation shaft 40. The opening posture is separated from the inner peripheral surface 220 of the case 20, and the closed posture is in contact with the inner peripheral surface 220 of the case 20.
（ダンパ動作）
便座５が直立姿勢にあるとき、流体ダンパ装置１０では、仕切り用凸部２３の端部２３１は、回転軸４０の円弧面４１０ｂとの隙間を介して径方向外側で対向している。この状態で、便座５が平伏姿勢に向けて回転する閉方向Ｓへの回転動作を開始すると、ロータ３０が中心軸線Ｌ周りに第１方向Ａに回転する。このため、弁体５０は、流体１２から圧力を受けて回転し、第２端部５２が第２凸部４６２の側に向けて移動する。その結果、弁体５０の第２端部５２は、ケース２０の筒部２２の内周面２２０に当接する（閉姿勢）。従って、弁体５０と筒部２２との間では流体１２の移動が阻止される。
(Damper operation)
When the toilet seat 5 is in the upright posture, in the fluid damper device 10, the end portion 231 of the partitioning convex portion 23 is opposed to the outer side in the radial direction through a gap with the arc surface 410 b of the rotating shaft 40. In this state, when the toilet seat 5 starts rotating in the closing direction S that rotates toward the flat posture, the rotor 30 rotates in the first direction A around the central axis L. For this reason, the valve body 50 receives pressure from the fluid 12 and rotates, and the second end portion 52 moves toward the second convex portion 462. As a result, the second end portion 52 of the valve body 50 comes into contact with the inner peripheral surface 220 of the cylindrical portion 22 of the case 20 (closed posture) . Accordingly, the fluid 12 is prevented from moving between the valve body 50 and the cylindrical portion 22.
これに対して、図１に示す便座５が平伏姿勢から起立姿勢に回転する開方向Ｏへの回転動作を行う際、ロータ３０が中心軸線Ｌ周りに第２方向Ｂに回転する。このため、弁体５０は、流体１２から圧力を受けて回転し、第２端部５２が第１凸部４６１の側に向けて移動する。その結果、弁体５０の第２端部５２とケース２０の筒部２２の内周面２２０との間には隙間があく（開姿勢）。従って、弁体５０と筒部２２との間では流体１２が通り抜ける。このため、仕切り用凸部２３が第１軸部４１の円弧面４１０ａに接する状態のときでも、ロータ３０には大きな負荷が加わらない。
On the other hand, when the toilet seat 5 shown in FIG. 1 performs the rotation operation in the opening direction O in which the toilet seat 5 rotates from the flat posture to the standing posture, the rotor 30 rotates in the second direction B around the central axis L. For this reason, the valve body 50 receives pressure from the fluid 12 and rotates, and the second end 52 moves toward the first convex portion 461. As a result, there is a gap between the second end portion 52 of the valve body 50 and the inner peripheral surface 220 of the cylindrical portion 22 of the case 20 (open posture) . Therefore, the fluid 12 passes between the valve body 50 and the cylindrical portion 22. For this reason, even when the partitioning convex portion 23 is in contact with the arc surface 410a of the first shaft portion 41, a large load is not applied to the rotor 30.