US 12,331,864 B2
Joint structure, joint unit and assembly method of joint unit
Hiroshi Imai, Saitama (JP); and Kazuki Hirai, Saitama (JP)
Assigned to Surpass Industry Co., Ltd., Saitama (JP)
Filed by Surpass Industry Co., Ltd., Saitama (JP)
Filed on Sep. 25, 2020, as Appl. No. 17/032,451.
Claims priority of application No. 2019-182196 (JP), filed on Oct. 2, 2019.
Prior Publication US 2021/0102649 A1, Apr. 8, 2021
Int. Cl. F16L 33/34 (2006.01); B29C 65/00 (2006.01); B29C 65/48 (2006.01)
CPC F16L 33/34 (2013.01) [B29C 65/48 (2013.01); B29C 66/5221 (2013.01); B29C 66/71 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A joint unit including a resin-made tube in which a liquid transferring channel extending along an axis is formed and a cross section orthogonal to the axis is round and a joint structure attached to an end of the resin-made tube, the joint structure comprising:
a main body;
a tubular part that is formed in a tubular shape integrally protrudes from and is formed unitary with the main body along the axis and has an inner diameter with an inner peripheral surface that holds an outer peripheral surface of the resin-made tube; and
a protrusion that is formed in a shaft shape integrally protrudes from and is formed unitary with the main body along the axis and forms, between the protrusion and the tubular part, an insertion groove in which the resin-made tube is inserted, with the protrusion also being inserted into the liquid transferring channel of the resin-made tube, the main body, the tubular part and the protrusion being a unitary one piece structure, wherein
the main body and the protrusion are formed with a coupling channel extending along the axis and coupling the liquid transferring channel and another channel,
a tip of the protrusion is disposed at a position closer to the main body than a tip of the tubular part,
the protrusion includes a constant diameter shaft portion extending for at least a majority of a length of the insertion groove, and a tip portion having an outer diameter that gradually decreases toward the tip of the protrusion, and
the tubular part has a constant inner diameter in a region from a base of the protrusion to the tip of the protrusion along the axis and has a shape in which an inner diameter expands at the tip of the tubular part in a region from the tip of the protrusion to the tip of the tubular part along the axis,
wherein
an outer diameter of the protrusion is larger than an inner diameter of the liquid transferring channel, an outer diameter of the resin-made tube is smaller than an inner diameter of the tubular part, and the tubular part is disposed on an outer peripheral side of the protrusion in a non-inserted state when the protrusion is not inserted in the liquid transferring channel of the resin-made tube, wherein insertion of the protrusion into the liquid transferring channel of the resin-made tube expands size of the outer peripheral surface of the resin-made tube over the constant diameter shaft portion to form an expanded cylindrical surface extending for at least a majority of the length of the insertion groove to be securely held by the inner peripheral surface of the tubular part disposed on an outer peripheral side of the protrusion.