US 11,927,240 B2
Rotary damper and manufacturing method thereof
Masato Yamashita, Hamamatsu (JP); and Keigo Ozaki, Brewer, ME (US)
Assigned to SOMIC MANAGEMENT HOLDINGS INC., Tokyo (JP)
Appl. No. 17/793,609
Filed by SOMIC MANAGEMENT HOLDINGS INC., Tokyo (JP)
PCT Filed Dec. 14, 2020, PCT No. PCT/JP2020/046456
§ 371(c)(1), (2) Date Jul. 18, 2022,
PCT Pub. No. WO2021/149394, PCT Pub. Date Jul. 29, 2021.
Claims priority of application No. 2020-006945 (JP), filed on Jan. 20, 2020.
Prior Publication US 2023/0062021 A1, Mar. 2, 2023
Int. Cl. F16F 9/14 (2006.01); F16F 9/12 (2006.01)
CPC F16F 9/145 (2013.01) [F16F 9/12 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for manufacturing a rotary damper including a lid configured to close an opening of a case, the method comprising:
placing the lid on the case so as to close the opening with the lid;
applying a pressure to the lid in a vertical direction which is a direction orthogonal to an upper surface of the lid,
measuring characteristics of the rotary damper in a state where the pressure is applied to the lid before the lid is fixed to the case;
fixing the lid to the case without displacing the lid when a measurement result satisfies a set value; and
displacing upward vertically or downward vertically the lid and then measuring the characteristics of the rotary damper again in a state where the pressure is applied to the lid in the vertical direction before the lid is fixed to the case when the measurement result does not satisfy the set value;
wherein the rotary damper further includes a protrusion protruding in the vertical direction and formed on one of the lid and the case and a groove having an arc shape formed on the other of the lid and the case,
wherein when the lid is placed on the case, the protrusion is brought into contact with a bottom surface having a gradient of the groove, and
wherein the lid is displaced by rotating the lid or the case while bringing the protrusion into contact with the bottom surface of the groove.