Abstract: A male joint includes a male joint main body and a valve element provided coaxially with a central axis of the male joint main body. The valve element includes a shaft portion and a valve portion coaxially provided at a tip end of the shaft portion. The valve portion has a first surface intersecting with the central axis and a second surface that is connected to an outer edge of the first surface and extends along the central axis from the first surface to a base end at a base end portion. The valve portion further comprising a groove having an annular shape centered on the central axis at a side portion and a deformation portion on a base end side of the groove.

Abstract: A pipe joint and a joint connection device have simpler configurations while preventing fluid leakage and absorbing misalignment of shaft centers. A pipe joint includes a male joint and a female joint into which the male joint is inserted. The male joint has a male joint main body and a cap that is fixed at a base end of the male joint main body, with a male joint O-ring interposed between the cap and the male joint main body. The cross-section diameter of the male joint O-ring is 3 to 10 mm, and a clearance-between the male joint main body and the cap is 3 to 13% of the cross-section diameter of the male joint O-ring.

Abstract: Provided are a pipe joint and a joint connection device that have simpler configurations and yet can prevent fluid leakage and absorb misalignment of shaft centers. A pipe joint includes a male joint and a female joint into which the male joint is inserted. The male joint has a male joint main body and a cap that is fixed at a base end of the male joint main body, with a male joint O-ring interposed between the cap and the male joint main body. The cross-section diameter of the male joint O-ring is 3 to 10 mm, and a clearance between the male joint main body and the cap is 3 to 13% of the cross-section diameter of the male joint O-ring.